THE ÜNr/ERSITY OF OKLAHCMA GRADUATE COLLEGE (VIREO ATRIGAPILLUS) SUBMITTED TO THE GRADUATE FACULTY. in partial fulfillment of the requirements for the

Transcription

1 THE ÜNr/ERSTY OF OKLAHCMA GRADUATE COLLEGE A BOEGOLOGGAL STUDY OF THE BLACK-GAPPED VREO (VREO ATRGAPLLUS) A DSSERTATON SUBMTTED TO THE GRADUATE FACULTY n partal fulfllment of the requrements for the degree of! DOCTOR OF PHLOSOPHY BY JEAN WEBER GRABER Norman, Oklahoma 1957

2 k BOEGOLOGGAL STUDY OP THE BLAGK-GAPPED VREO (VREO ATRGAPLLUS) APPROVED BY j d s A J é DSSERTATON COMMTTEE

3 ACKNOWLEDGEMENT wsh to acknowledge the ad gven me by many persons and nsttutons. The followng lbrares were used; Southwest Texas State Teachers College, San Marcos, Texas; Unversty of Texas and Texas Hstory Center, Austn; and Unversty of! llnos, Champagn-Urbana. Plant specmens were dentfed by George J. Goodman bf the Unversty of Oklahoma, B. L. Turner and W.. McCart of the Unversty of Texas, and Rogers McVaugh of the Unver- sty of Mchgan.! Stomach contents were dentfed by Mlton W. Sander-1 son of the llnos Natural Hstory Survey. Advce on statstcal data was gven by P. J. Clark of the Unversty of Oklahoma. Specmens were borrowed from the followng: Unted States Natonal Museum, Amercan Museum of Natural Hstory, Chcago Museum of Natural Hstory, Unversty of Mchgan Museum of Zoology, Unversty of Texas, Agrcultural and Meehan^ j cal College of Texas, Unversty of Kansas Museum of Natural Hstory, Museum of Vertebrate Zoology (Unversty of 111

4 CàllTornTa)7 lïmë ota Müsëù1m~ôr~]ï^^^ pf Mnnesota), Strecker Museum (Baylor Unversty), and Muse-- urn of Northern Arzona. The followng nsttutons furnshed me nformaton; Museum of Scence, Boston, Mass.; Brtsh Museum of Natural Hstory; Unversty of Oregon; Chcago Academy of Scences; Nevada State Museum; Los Angeles County Museum; Alabama Museum of Natural Hstory; St. Joseph Museum, St. Joseph, Mo.; Peabody Museum, Salem, Mass.; Berkshre Museum, Pttsfeld, Mass.; Kansas Hstorcal Socety, Topeka; Academy of Scence,; jst. Lous, Mo.; Stanford Unversty, Stanford, Calf.; New ; fork State Museum; Academy of Natural Scences, Phladelpha; &anta Barbara Museum, Santa Barbara, Calf,*; Prnceton Muse- " urn of Zoology; Hastngs Museum, Hastngs, Neb.; Lousana State Unversty; Southern Methodst Unversty; Sul Ross State Teachers College, Alpne, Texas; Dallas Museum of " Natural Hstory; Carnege Museum; Yale Peabody Museum; CornaL. Jnversty; Texas Game and Psh Commsson; and the U. S. sh and Wldlfe Servce.! The followng persons have gven me nformaton con cernng the speces: Geth Osborne, Edward G. Frtz, Mrs. T. E. Wnford, and Mrs. Kennedy England, all of Dallas, Texas; Pred S. Webster, Edgar Kncad, and Roy Bedcheck, all Pf Austn, Texas; Edna Mner and Carl Aken, Houston, Texas; Fl*ed W. Jopn, Vernon, Texas; Lena McBee, El Paso, Texas;.. Kent Rylander, Denton, Texas; G adds Taylor, Tyler, Texas; v

5 Besse Red, Slsbee, Texas; C. Terry Gll andrby Davs, Harlngen, Texas; Mrs. Mke O'Nel, Commerce, Texas; Mrs. Robert N. Molloy, Corscana, Texas; Mrs. Conger Hagar, Rockport, Texas; Warren M. Pulch, rvng, Texas; Joe Baley, Canyon, Texas; Wm. McMllan, Lubbock, Texas; Nell Amthor, Bastrop, Texas; L. R. Wolfe, Kerrvlle, Texas; Carl W. Gugler, Unversty of Nebraska, Lncoln; Jerry Stllwell, Fayettevlle, Ark,; T. D. Burlegh, Moscow, daho; Edth Force Kassng and Orrn W. Letson, Tulsa, Okla.; F. M. Baumgartner, Stllwater, Okla.; Alden H. Mller, Berkeley, Cal.; Alexander Wetmore, Herbert Fredmann, and H. G. Degnan, all of the U. S. Natonal Museum, Washngton, D.C.; Dwan Warner, Unversty of Mnnesota, Mnneapols; H. C. Oberholser, Cleveland, Oho; Robert T. Moore, Los Angeles, and George H. Loweÿ, Jr., Lousana State Unversty, Baton Rouge. The followng have gven me fnancal ad: the Natonal Scence Foundaton (fellowshp 19BB-B6), Women s Garden Clubs of Amerca (Rosebud chapter, actng as my sponsor), and the Scholarshp Commttee of the Unversty of Oklahoma, The followng persons permtted me to do feld work on ther propertes: W. H. Church, Shrum Lee, and Mr. Salyej all of Cogar, Oklahoma; Haney Thornton and D. R. Capps, Jr., Wmberley, Texas; W. B. Rankln, Menada Ranch, Uvalde, Texas;; and N. D. Blackstone, Sheffeld, Texas. am also grateful for permsson to do feld work on É1 Rancho Cma, Wmberley, Texas, whch s owned by the V

6 Hous t on G oünc of the Boy SëôütT^ôT'Amêrlcëü TSeTParkTServ^ ce of the Bg Bend Natonal Park was very helpful when was dong feld work there. To the followng persons wsh to express my grattude especally; Mrs. M. M. Nce, Chcago; Mrs. Love Whtaker, Elroy Rce, Davd F. Parmelee, John C. Johnson, Jr., Don Baepler, and Hugh Land, all of Norman, Oklahoma; and Allan R. Phllps. To George M. Sutton, who drected ths study, and to my husband, Rchard R. Graber, who helped me n a multtude of ways, owe much. V

7 TABLE OF CONTENTS Page LST OF T A B L E S... x LST OF M A P S... x LST OF G R A P H S... x LST OF P H O T O G R A P H S...xl Chapter. NTRODUCTON TECHNQUES AND MATERALS U S E D LFE H S T O R Y... 5 V. H A B T S V. FOOD AND F E E D N G V, ECTOPARASTES AND DSEASE...?6 V. T A X O N O M Y V, D S T R B U T O N X. OTHER VERTEBRATES N AREA OCCUPED BY BLACK-CAPPED VREO AND TS RELATON TO T H E M X. H A B T A T X. D S C U S S O N X. SUMMARY BBLOGRAPHY v

8 Page APPENDCES P H O T O G R A P H S v

9 LST OP TABLES Table Page 1. Observatons of Nest (N2) on Fourth Day of n c u b a t o n Observaton of Nest (N2) on Fourteenth Day of n c u b a t o n » Observatons of Nest (Nfl): Second Brood, ncubaton on Thrd Day before Hatchng Daly Weghts of Nestlngs n G r a m s » Analyss of Nestng Success for Three Years Analyss of Egg L o s s Analyss of Loss of ncubated Eggs and N e s t l n g s Analyss of Stomach Contents Food of Black-capped V r e o Geographc Varaton n Measurements of Adult M a l e s Varaton n Measurements of Dfferent Age G r o u p s Dstrbutonal Records of Vreo atrcapllus Frequency (n Percent) of Woody Plants n Oklahoma Q u a d r a t s... ll 6 lj.. Frequency (n Percent) of Woody Plants n Texas Quadrats...l) 7 X

10 Table Page 15. Number and Sze of Lvng Trees n Ffty-four Oklahoma Quadrats... l.j[r 16. Number and Sze of Lvng Trees n Thrty-fve Texas Quadrats n Hays and Comal C o u n t e s... llj.9

11 LST OF MAPS Map Page 1. Terrtores n Oklah.oma Study A r e a Dstrbuton of Vreo atrcapllus Records n.-nebraska Dstrbuton of Vreo atrcapllus Records n K a n s a s Dstrbuton of Vreo atrcapllus Records n Oklahoma Dstrbuton of Vreo atrcapllus Records n T e x a s Dstrbuton of Vreo atrcapllus Records n M e x c o... 3O X

12 LST OF GRAPHS Graph 1. Comparatve Data Showng Egg Layng Actvty Durng Dfferent Weeks of the Layng Season n Oklahoma and Texas.. Page Growth Curves of Ng Brood Daly Weghts of Mxed Brood n Black-capped Vreo N e s t ^. Daly Weghts of Mxed Brood n Bell's Vreo N e s t....l Feedng Rates n a Nest wth Pour Black-capped Vreo Chcks... $0 6. Temperature and Precptaton n Breedng Habtat... l5^ 7. Temperature and Precptaton n Western Texas,, and. Western Oklahoma Temperature and Precptaton n Localtes North and East of the Breedng Area and Those at Kerrvlle, T e x a s...l58 9. Temperature and Precptaton of Wnterng and Breedng Habtats O x

13 LST OF PHOTOGRAPHS Fgure Page 1, Newly hatched vreo chck and cowbrd c h c k s , Nest s t u * Adult male at n e s t _. Adult female at n e s t Sght males showng correlaton between darkness of head and a g e Habtat n Dewey County, Oklahoma Habtat n Comanche County, K a n s a s Habtat n Caddo County, Oklahoma Heght of vegetaton n Caddo County, Oklahoma, habtat Habtat n Comal County, Texas Closer vew of Comal County, Texas, habtat Habtat n Coahula, Mexco Wnterng habtat n southern Snaloa, M e x c o Detal of habtat n southern Snaloa, Mexco Wnterng habtat n Nayart, Mexco Detal of habtat n Nayart, Mexco Xlll

14 A BOEGOLOGGAL STUDY OP THE BLAGK-GAPPED VREO (VREO ATRGAPLLUS) CHAPTER NTRODUCTON A study of the black-capped vreo (Vreo atrcapllus) was undertaken to learn more of ths lttle known speces, and to learn why t appears to be so lmted n ts dstrbuton. To accomplsh ths, the habts of the brd, ts habtat preferences and the envronmental factors thereof, ts populaton dynamcs, and ts hstory (as much as could be ascertaned) were nvestgated. The black-capped vreo was descrbed as a new speces n 18^2 by S. D. Woodhouse, M.D., the physcan and bologst of an exploratory expedton down the Zun and Colorado Rvers under Captan Lorenzo Stgreaves of the U.S. Corps of Topographcal Engneers. Vïoodhouse's two specmens were taken on May 26, 18^1, along the Ro San Pedro n southeastern Valverde County, Texas. J. H. Clark, one of the naturalsts of the Mexcan Boundary Commsson, collected a specmen n the same area. Ths specmen, now n the Amercan Museum of

15 F â m r m Hstory, 2 descrbed by S. F. Bard n hs secton on brds n the 18$8 ; Report of the Pacfc Ralway Survey. A fourth specmen was taken at Mazatlan, Snaloa, jmexco, by Colonel A. J. Grayson n the 860's. These four speclmens were the only ones known when Coues publshed Î Brds of the Colorado Valley" n 18?8. n ths year, n Comal County, Texas, the nest and eggs were dscovered by W. H. Werner. There followed a flurry of artcles n the Bulletn of the Nuttall Ornthologcal Club n l8?9. n 886;,! j N. S. Goss found the speces n Comanche County, Kansas. Some nterest was taken for a whle thereafter, but from the turn of the century lttle note was pad to the speces, except for a bref study publshed by Bunker n 191O dealng wth the brds of Blane County, Oklahoma.

16 CHAPTER ; TECHNQUES AND MATERALS USED! have attempted to survey the breedng range of the black-capped vreo, makng specal effort to fnd the spece? n areas where t formerly occurred, where t occurs at presn pnt, and n new localtes. Ths nvolved travel from Hodgeman County, Kansas, through central Oklahoma, Texas, and! northern Mexco to central Coahula. also made observatons Î! pn the brd and ts surroundngs on ts wnterng grounds n j jsnaloa and Nayart, Mexco. Vegetatonal factors of the habtat were examned. checked number, frequency, and estmated sze of the woody plants n quadrats about the nests. Quadrats $0 ft. square were lad off wth two 100 ft. balls of cord. Woody domnants n the wnterng habtat were dentfed. R. R. Graber determned the age of tree samples by the rng method. The Stuaton of nests was noted and measurements made wth a 72-nch steel tape. j n studyng the lfe hstory and habts, brds were captured, weghed, and banded. Brds were captured wth slk 3

17 4 TôWTng" n6%8^#n5ïcreë8#; FsrnaLnd-wtld Lfe Servce bands and wth colored pyraln bands. Nestlngs were banded on the sxth or seventh day after hatchng. For all weghngs used portable, trple-beam balances of 100 gram capacty and.01 to.001 g. accuracy. One juvenle was } kept n captvty for sx weeks. Eggs were marked wth a lead pencl, weghed, and a few were artfcally ncubated. ; Observatons were made at nests from home-made, cloth blnds;} h X 30 feld bnoculars were used. ; Stomachs were saved, and ther contents dentfed. One hundred and seventy-fve museum specmens were measured and examned for varaton and molt. j 1! Photographs were made wth a 35 mm. Exakta and a 1 2 1/1^ X 3 l/l). Crown Graphc. A few recordngs of temperature! were made wth a maxmum-mnmum recordng thermometer.

18 CHAPTER LFE HSTORY Most of the lfe hstory materal was obtaned n devoted all of that year to such observatons. When! began the study, had never seen or heard the speces, so l felt that becomng thoroughly acquanted wth t would be my frst step. began gong to the oak-cedar scrub forest jof Caddo County, Oklahoma, n md-march, 195f» frst heard and saw the black-capped vreo on Aprl 2$, 195^+«Arrval On ths approxmate date of arrval, a brght, warm, sprng day, saw four males, all of whch were sngng spr- jtedly. No females were seen. On our next trp. May j., females were present. ^s early as Aprl 1?. n 195$, males were found n ths area A careful search faled to reveal any! jfemales on that date or on Aprl 20 and 2$. On Aprl 30, females were observed. n 1956, begnnng March 1, made daly searches n Hays and Comal countes, Texas. Males were [frst observed on March 2., females on Aprl 7, so t appears that the males regularly arrve a week or two n advance of

19 females7 LWd~"(T887)"TMTcâfM'e^arlîèr than females, but only by a day. Arrval dates for varous localtes are as follows: Localty Bandera County, Texas Observer Ragsdale (Cooke, 1888) Date March 19 j kendall County, Texas Brown (1882) March 27 Kerr County, Texas Lacey (1911) March 19 (earlest ) March 2l (average ) Travs County, Texas ballas County, Texas Cooke County, Texas Shpwash (Kncad, 195k) March 3 : (earlest ) Smmons (192$) Late March Kelley (1935) Aprl 1 Stllwell (1939) Aprl 9 1 (earlest): Ragsdale (o. ct.) Aprl 17 1 Goss (188$) Late Aprl These records ndcate a gradual movement northward n March and Aprl, the northernmost localtes beng reached by the last of Aprl. Terrtores On arrval, the male establshes a terrtory, and! ths remans hs as long as he chooses to, or can, defend t. Observatons of banded brds for a perod of three years on al study tract n Lone Rock Townshp (secton 18 and adjonng! sectons to the southeast and southwest), Caddo County, Okla- homa, ndcate that male black-capped vreos are very much

20 j 7 râlït'aclïë^ t l r e f ^ t W f 1 TkëTy To move'tar 1! from them. ; Nne of twelve males banded n 195 returned n 1955» jof these, four occuped dentcal terrtores for the two jseasons, and fve occuped terrtores adjonng those of the (frst season. One of the latter changed terrtores n md- season. n 19^6, found fve males that had returned to the area for the thrd year. Three of these mantaned the same ' Terrtores all three seasons, and two occuped the same ter4 jrtores for the last two seasons. Both of the latter had moved to adjonng terrtores after the frst season. Pour! males banded n 1955 returned n Of these, three re-! maned on the same terrtores they had had before, and one moved nearly half a mle, though hs mate of the former season remaned on ther former terrtory. Both the brd whch moved and hs former mate had new mates. jl955* Fve of twelve females banded n 1954 returned n One remaned on the same terrtory, two were on terrtores adjonng ther former terrtores, and tv/o had! moved about a quarter of a mle. n 1956, found two of the females banded n 1954* One may have occuped the same terrtory all three summers, though dd not see her n 1955* jthe other had moved to a terrtory adjonng her 1955 terrtory whch n turn had adjoned her 1954 terrtory. Thus she had occuped three adjonng, though separate, terrtores n three seasons. Two females banded n 1955 returned n

21 8 and e ach oc c up è d the' terrtory t had had tle" prevous se a- son. The terrtory actvely mantaned by the male thrcw^out the season ncludes the space n whch the pars feed,! lengage n all ther daly actvtes, and nest. n some n- ] ^stances they leave ther terrtores to reach waterng areas! shared by all. The boundares of terrtores studed changed but lttle n three years of observaton. f a terrtory s unoccuped, neghborng brds tend to occupy t, thus enlarge lng ther own terrtores. The male that changed terrtores n md-season was probably drven from hs orgnal area be-! cause he was n poor condton as the result of a foot nfec-f ton. There were a few unmated males n margnal areas that jmoved n to gan a mate or a more desrable terrtory when- jever chance allowed. Terrtoral lmts were determned by watchng banded, brds throughout the season and by "drvng" them. drove the males slowly to ponts at whch they would go no farther and turned back* n some cases the neghborng male came to that place and announced hs boundary. measured some of these areas usng a 100 ft. cord wth whch followed jstraght lnes across the greatest length and breadth of the terrtory* measured only terrtores wth whch was most! jfamlar, but others dd not appear to dffer markedly. The measurements of fve terrtores n 1 % \ \ were:

22 Breadth. Length Area n Acres 1 25 feet feet b k.03 1^ These measurements are only approxmate because of the rough-' ness of the terran. Terrtores n other localtes n sm- jlar habtat (oak-cedar scrub) appeared to be about the same sze. Terrtores n burnt-over, mxed-decduous scrub seemed : to be slghtly larger. Hensley (1950) found the terrtory of a par of Bell's vreos (Vreo bell) n llnos to be 3*1! 'acres n sze. Map plots the terrtores n the study area* These! vnced, s because the tree growth n such places s of the form a mosac about the canyon heads, and ths, am con proper sze and knd. Bunker (9O) expresses ths same dea, namely, that the brd chooses not the lay of the land, but the vegetaton. The chef means of mantanng a terrtory s song, boundares beng establshed and the presence of the male an bounced to females thus. Conflcts between males may occur before the females arrve, but those that have wtnessed jtook place after nestng had started. have never seen any more volent acton taken than that of flyng (pouncng) at each other and chasng. There s a specal terrtoral song 'f a rapd, bubblng song, much lke (f not the same as) the

23 10 MAP TERRTORES OF BLACK-GAPPED VREOS N THE COGAR, OKLAHOMA, STUDY AREA, 195> - 19^6 1 rnle Woo0 clfm CuHvde held Pasture terrtory t J Ow cab/n ra s ru re d Wood fa n J Wood/and C J ' / C

24 11 jcmr'tstïlp ^BŒth coxr t shp-and -tetrl-^ toral songs may well be the result of the agtaton felt b y, the snger at such tmes. The followng are descrptons of conflcts between brds: Two males approached each other sngng the regular song and occasonally scoldng untl one was perched fve nches above the other on a dead lmb n the top of an oak. t The frst male quvered hs wngs and sang the terrtoral song. The male below also sang the terrtoral song, and moved hs head from sde to sde n a reptlan manner, hold- jng hs mandbles open. After half a mnute, both brds left^ each gong to hs own grounds. The scold notes used were 'dfferent from those the speces used toward human ntruders. One note was a hgh-ptched "scref, " the other a sharp "chtj cht-cht. The frst male used both, the second gave only the "scref" as he approached. R. R. Graber saw an nterestng encounter. Two jneghborng males were sngng regular songs as they flew from tree to tree, gradually approachng each other. Fnally jthey confronted each other n two dead blackjack oaks about LOO feet from the nest of one of them. When they were about four feet apart and about the same dstance above ground, they began sngng terrtoral songs. As they hopped about the branches, movng slowly closer, they flcked ther wngs, pngng lurously all the whle. When they were about two f8 8 t apart, one flew nto the tree of the other, and the

25 12 T^ter darted a: teè n v M e r' maîmïg a'dsmclt c They both returned to ther own trees for a moment, and the ; whole affar was repeated wth an nterchange of roles. Then, whle contnung terrtoral song and flckng the kngs, each wthdrew toward hs own terrtory, and began sng;!! ng occasonal phrases of the regular song. When about 15 to 20 feet apart, they were sngng regular songs entrely. n another nstance, a male chased a stranger (unjbanded male, new to area) about 200 yards from the young brds the former was feedng. Whle the two adult males were; parryng on a vocal battle from tree to tree, a thrd male joned the fray, so that at one tme all three were sngng jonly a few feet apart. On another occason, a male whle feedng hs fledg- ng8 wandered nto a terrtory adjonng hs own. He saw me jand scolded. The propretor of the terrtory appeared, and both males scolded me. One of the juvenles came near, and ' jts parent caught an nsect, but at the same tme decded to attack the other male whch was qute close to the young brd. He chased the brd away, carryng the food all the whle, then returned and fed the juvenle. The frst mate of a female who chose the male of an adjonng terrtory for her mate upon startng a second broodj joften came to the edge of ther terrtores and engaged n dspute wth the male who had stolen hs mate away. He was probably tryng to follow the female to her second nest not J

26 13 par away, êæa was halted bÿ her "hew" mate ât thë-tërrrtôrÿ- boundary. : :! have never observed a conflct of any sort between : two females or between a male and a female. : Par Formaton! Pars were formed mmedately upon arrval of the fe- males. The female appeared to choose the male and terrtory ; together, matng wth a male on or near the area to whch she; became attached. Pars appeared rather stable. Changes occurred when one of the par faled to return to breedng grounds after wnter, when one or the other was ncapactated by an accdent, or when a male was occuped wth carng for the frst brood and a nearby male was avalable for startng the second brood. Twelve pars were banded n 19$^. The only female! that know to have been double-brooded changed mates be- tween broods. n l re-nestng attempts nvolvng sx pars, bnly one par changed mates, ths exchange nvolvng the double-brooded par. - know of two pars that were double- brooded n and both remaned mated for the second broodj n seven re-nestng efforts, nvolvng sx pars, only one par changed mates. beleve that pars reman mated throughout a season because re-nestng and startng of second! J broods begn at dfferent tmes, and therefore only the two brds nvolved are lkely to be at the same stage n the!

27 l. ^productve cycle. THe members of^ only" lwo ~pars ^survvedrn ;three seasons. One par know were mated n and 1956, and probably n 1955, though dd not see the female that year. The other two remaned mated for two seasons, through a total of at least three nestngs, but separated the thrd jseason. Two pars returned n 1956 for ther second season, land one remaned mated; the other changed mates. Courtshp and Copulaton Courtshp conssts of song and dsplay. observed ;,courtshp by song far more often than that nvolvng dsplayj jthere s a specal courtshp song whch s made up of a seres of low, rapd, bubblng notes, entrely lackng the j characterstc phrasng of the regular song. The male fol- lows the female about the terrtory sngng to her. Often have watched the female alght, then the male about a foot away from her, commencng hs courtshp song. n one courtshp flght wtnessed, the male flew n j a downward arc from a perch 30 feet hgh to a perch three feet jgh, flutterng hs golden-tnted wngs and exposng hs brllant back whle sngng the courtshp song before the female who was perched near the pont of hs departure. She then flew to where he alghted. n another nstance, the male fed a juvenle of the pmr»'s frst brood, then he left hs perch n pursut of the female. Both brds gyrated about the sky some 1^0 feet up, the male followng the female closely.

28 S 5ut né ver 'c â W n a g Hïé Chppjîg-8ôûms-t''^^'':ûp7"' tup ) were gven durng the flght, then the male alghted and sang a courtshp song. One dsplay whch mmedately preceded copulaton Conssted of several short flutterng flghts about a foot jabove the perched female, whle sngng the courtshp song. These flghts may have been attempts to mount the female. The two tmes watched copulaton, the female was perched about eght feet up n a tree. The male hovered over her, then settled lghtly on her back for a moment. Copulaton took place n md-mornng both tmes. ' The Nest Ste The male covers hs terrtory thoroughly before the Arrval of the female, and whle dong so he looks for nest Ltes. n fact, have seen a male buld the rm of a nest kurng ths tme. have watched males go to a lkely-lookng crotch and examne t carefully, even crcumscrbng an arc wth the head between the branches as f weavng fbers or measurng the wdth between them. have also seen a whte- pyed vreo (Vreo grseus) do ths same thng. When the female arrves, the par wanders about the terrtory lookng at nest stes together. suspect that the female makes the choce, for saw a par examne a crotch to whch the male had already attached a few wsps of spderweb, but they began buldng the next day at another ste. Too,

29 6 p â W ''â rrëm â lw 'l3 T lt a 5 g "a n ïë s t-t ô P " "b H y T ïë r s ê lt j Whle the male cared for the frst brood. know, also, of! two unmated males that selected typcal nest stes and bult the rms of nests but never fnshed them. One of these jbult two nest rms durng the summer. The completon of a nest appears to requre the attenton and efforts of the fe- male. watched one par lookng for a nest ste. Both : flew down to and nspected the forked end of a certan small branch of a blackjack oak. The male tred repeatedly to pull off a small dead twg that stuck nto the openng of the crotch, R. R. C-raber observed another par behavng n the same manner. Ths par went nto two separate clumps of oaks and looked at stes. They peered at the crotches closely, sometmes nbblng at the twgs. The nest s generally placed almost as far out on the branch as t s above the ground. The average dstance from the trunk to the nearer edge of the nest was 29 nches and the average heght (ground to the rm of the nest) 35.1 nches n 52 Oklahoma nests. n 25 Texas nests, these measurements jwere 28.8 and 5.7 nches respectvely. Frequently a nest s bult n a shoot. The average dstance from the tp of the branch n 83 Texas and Oklahoma nests was 5 nches, the greatest dstance beng 13 nches. The heght of 67 Oklahoma nests ranged from 8 to 66 (average, 3l.5) nches. That of 3k Texas nests n 1956

30 17 ^ranged from 27 to h, nches (average, Smmons (1925) gave nestng heghts n Texas as two to sx feet, rarely 15» usually four. Fve nests n central Goahula, Mexco, were lone to two feet above the ground. Nests placed, n Spansh oaks n Texas had an average heght of 5 9«6 nches. The deer browse lne on these trees was just a lttle under fve feet; ^! Nests n the same area n cedars, whch are never browsed, had an average heght of 39*7 nches. The sze of the tree or shrub probably also affects the locaton of the nest. t n 70 Oklahoma'nests examned by me, sx speces of trees were chosen for nestng: Speces Number of Nests! Blackjack oak (Quercus marlandca) 5l Post oak (%. stellata) 12 Chnquapn oak (Q,. muhlenberg) 3 Buckeye (Aesculus glabra) 2 jredbud (Cere s canadenss) 1 jposon vy (Rhus toxcodendron) 1!% found one old nest n a Red cedar (Junperus vrgnana) jwhch am certan was that of a black-capped vreo. n 37 Texas nests, the speces of trees chosen for nestng were:

31 18 lës " mrntër of "Jëst's Spansh oak (Quereus texana) 12 Evergreen sumac (Rhus vrens) 11 Mountan cedar (Junperus ashe) 9 Sumac (Rhus lanceolata) 3 Lve oak (g. vrgnana) 1 Whte oak shnnery (^. brevloba) 1, Of fve nests found n central Goahula, Mexco, four were n scrubby oak (Quercus sp«), one n madrono (Arbutus jtexana). Nests have been found also n elm (probably Ulmus 'amercana) (Goss, 188^); dogwood, wld plum, chnaberry :(Bunker, 1910); mesqute (Dave, 1098); and elm (probably jcedar elm, Ulmus crassfola) (Smmons, 1925). An unusual nest ste n a pne was descrbed by Sngley (188?). Certan nest stes are used repeatedly by black- capped vreos, for have found an old nest of the prevous season on the ground beneath occuped nests on several occasons. have observed males burst nto courtshp song as they hopped about old nests. One unmated male regularly vsted an old nest and sang courtshp songs n the tree above t. Fnally the old nest fell, and he bult a nest rm n the same crotch. Two stes were used for at least three lyears n successon. Whle the sght of an old nest defntely stmulates the brds, the locaton tself may be attractve. n 1954 removed a nest and ts crotch; the

32 19 folïowïng à d par 6frëo8 bult n the' same tree n a crotch near the ste of the 195^1 nest. ' The suggeston has been made (Bunker, 9O) that the : nest of the black-capped vreo s placed n the center of a jclump of bushes, whle that of Bell s vreo s placed at the ledge. n 31 of 70 Oklahoma nests, and 25 of 38 Texas nests, the nest was placed n the center. n the remanng $2 nests (13 Texas, 39 Oklahoma) the nest was placed at the edge. jhave seen a number of Bell s vreo nests that were n the : jcenterj therefore ths does not seem to be a very good way tb dstngush between the two.! j The Nest The nest s a cupped, pensle structure, typcally vreonne. Brewster (1879), Goss (1885), Dave (898), Bunker (9O), Smmons (1925), and Morse (927) gve descrptons of nests. Average measurements of 1^5 Oklahoma nests are; Used Unused Dmenson Nests (8) Nests (27) Outsde depth from rm to bottom 6.2j. cm. 5*86 cm. Largest outsde dameter at rm 5*52 5*93 Thckness of wall at rm (greatest) O nsde depth from rm to bottom 3»90 3*72 jused nests are those from whch young have fledged or those whch have been occuped for some tme. those n whch there have been only 6R2S. Unused nests are made ths

33 arstjîc^fon-vd - ^ ü w T d r -dt^^^^ 20 lng young brds n the nest. t appears that such dstorton as an elongaton produced by the weght of the young brds. Many nests are very compact wth felted walls whch become hard lke paper mache when weathered. Whle some are rather thck, many are qute thn at a pont just below the rm and pull apart at ths pont when there s much weght r the nest as s the case when there are two cowbrd chcks n ; the nest. The nests vary n shape and can be descrbed as : urn-shaped, sphercal, or cup-shaped. The outsde often has ; a pecular mottled appearance. As yet no one has gven a good means by whch to dstngush the nests of Bell s and black-capped vreos, and fnd that cannot tell them apart : wth certanty, though ths may be easer n places where the habtats of the two speces do not overlap. The materals used n constructon of nests were dead! j leaves, dred grasses, plant fbers, cottony plant substances^ cedar bark, paper, wool, and spder-web or smlar substances (caterpllar slk). The chef constructon materals n nest3 bult n oak-cedar habtat were cedar bark and oak leaves whch were bound together wth spder-web. n areas Where there are no cedars, grass and grapevne bark were used jnstead of cedar bark. n Mexco, the dred, paper-lke leaves of yucca were used. Thus the structure of the nest reflects the nature of the habtat. Bts of paper, spder cocoons, or other whte, tssue-thn materals are often

34 21 ; (ëc or a t r ÿ ë ly W T M spaj^së-^ln^ ng s of fne grass stems and pancles. Nest Constructon The materals for the nest are for the most part, gathered nearby. have watched both members of pars go to : j cedars close to nests they were buldng and pull small strps of bark from the lower, almost horzontal branches. have seen one female fly down and pck up a dead leaf from,! the ground not ten feet from the nest ste. have seen a j male tuggng at leaves on a dead branch of an oak about three feet above the ground. The nest he was startng was about d : or 15 feet away. have seen a par n Texas strppng bark from a mustang grape about ten feet from ther nest ste. One male on my study area n Oklahoma carred a pece of ts4 sue paper up nto a cedar. There he tore off small peces and carred them to the nest about thrty feet away. R. H. Graber and have both watched females gatherng spder-web from the topmost branches of dead oaks whch were close to ther nests. The length of tme requred for completon of the nest vares wth the par and the season. Frst or early summer nests are usually completed n four or fve days. Later nests and those for re-nestngs are usually more rapdly jbult. n one case, the total tme lapse between the loss of hatchlngs and the layng of the frst egg n the thrd nest

35 22 wa Tve days. The dngést tme observed between the begn- hng of buldng and the layng of the frst egg was 16 days. The perod between the completon of the nest and layng of. the frst egg s usually a day. Although both sexes work at buldng the nest, the! female accomplshes more snce the male pauses to sng and defend hs terrtory. Some males appear to be rather neffcent at buldng. observed one whose contrbuton toward buldng was to brng a bt of materal to the partly fnshed cup and just drop t n. have seen some females carry great mouthfuls (many peces) of materal to ther nests. observed one par from 12:00 noon to 1:00 p.m.! workng on a half-bult nest and found that they made 22! trps wth nest materal. The male made eght trps, the fe-^ male ll _. The male came and sat on the nest twce wthout brngng materal, the female dd ths once. The male sang short snatches of song as he worked. Sometmes he merely accompaned the female as she got materal and brought t to j the nest. never saw hm work at weavng wth hs bll as dd the female. He lmted hs buldng to sttng n the \ best and turnng about, fttng t to hs body, Bunker (1910) descrbed the begnnng of the buldng of a nest. He sad the brd attached fbers to the twgs makng a frnge, then t flew down, caught up a fber n ts bll, and flew to the opposte sde of the crotch to attach lt. have never observed ths stage of nest buldng, for_

36 23..-, M # M --- «1 ^ "?-- f remaned n the vcnty of a barely-started nest, tne brds nvarably deserted. Most of the nests watched were already a shallow platform of fbers, and as materal was 'added the brds sat on the nest, shapng t and makng t deeper by stretchng the loosely connected network. After a slow start (n terms of the amount of structure made), the brds buld rapdly for a day or two, addng the bulk of the : nest, then addng the lnng slowly. Nests are never re-used; ;! a new nest s bult for each clutch. Pour nests are the most ; have seen any one par buld n a season. ; Layng Graph pctures the layng of eggs n nests under observaton. found eggs hatchng as early as Aprl 23 n Hays County, Texas. n Caddo County, Oklahoma, the frst eggs were lad n late Aprl and early May. made an effort to determne the tme of layng for four dfferent females, and found that they lad at about 6:00 a.m. n June n central Oklahoma. n each case, the daly procedure durng egg-layng was much the same. The sngng of the male, at about 5.*00 a.m., was the frst evdence of actvty of the par. nest, but never went down to t. The male came toward the The female came to the nest; la lttle later (10 to 20 mnutes before layng) and got on jt. n layng, the female, havng been sttng rather deep jn the nest, rose up, arched her tal downward, pushed her j

37 2 4 GRAPH COMPARATVE DATA SHOWNG EGG LAYNG ACTVTY DURNG DFFERENT WEEKS OF THE LAYNG SEASON N OKLAHOMA AND TEXAS Aprl May June July August Texas, Oklahoma, 1954 Oklahoma, 1955

38 2S læe'nes^, wïïîle he f Tor^ p art s 'rôs W but of the nest, and appeared puffed out. After a few sec- onds, she settled agan. Upon flushng her, found the new ; ;egg not yet dry. f left undsturbed, she contnued to st j on the nest for 20 to.0 mnutes before leavng. ; Both brds st on the nest durng at least part of j the day on whch the frst egg s lad. watched one nest from to 10:35 a.m. The female got on the nest at 5:4^; lad at 5:57, and remaned untl 6:30. After a bref absence she returned to st on the nest for a total of one hour and lj.6 mnutes (ntervals of 31, 12, 33, 15, and 15 mnutes); thd male was on for one hour and 27 mnutes (ntervals of 1, 31,! l8, and 37 mnutes); and the nest was unattended for two j perods (19 and 17 mnutes). have seen other black-capped jvreos on ther nests after the layng of the frst eggs, but they dd not spend the nght on the nest untl the second or thrd egg had been.lad. So have counted ncubaton as startng on the day precedng the frst nght spent on the 1 best. t would seem that ths procedure would be detrmental jto development, but t does not appear to be so. Experments have ndcated that pheasant eggs can tolerate exposure to jtemperatures as low as 4 5 for perods up to eght hours 'durng the frst two weeks of ncubaton wthout lowerng hatchng success (MacMllan and Eberhardt, 1955). thnk ;the habt of daytme coverng of the eggs as soon as they are lad has survval value for the black-capped vreo n that n

39 26 th 18 manner the y "ar e r ds (Molotlrus later).! watched one female lay three eggs, fndng that she lad egg #1 at a.m., egg #2 at 6:0$-08 a.m., and egg #3 lafter 6:lj. a.m. (the male was on the nest untl then). n jevery case have observed, layng has occurred on consecu- jtve days. The Clutch Four eggs usually comprse a clutch. n nests, there were four eggs; n 26, there were three. However, n! ' j some nests holdng three eggs, four eggs may lave been lad, one havng been removed before checked the nest. found 1 no ndcaton that clutch sze n the north was larger than that n the south. have never found a nest wth more than four eggs. f an egg s removed durng layng, the clutch may be completed, but t wll consst of no more than three jsggs. f more than one egg s removed, usually the nest s (deserted, unless cowbrd eggs replace the loss. have recj lords of seven second nests contanng four eggs, and of only pne contanng three. n one case, both the frst and secondj clutches conssted of three eggs. n 19^^ n four nestngs j one female lad clutches of four, two (nterrupted by cowbrd), two (nterrupted), and three eggs (total; 11 eggs). n 1955 she lad three four-egg clutches. She weghed 9.1^5 grams n 1954* 8nd 9'$0 g» n 1 95$, so that n both seasons she lad

40 27 very nearly twceher own weght (egg w e g h t : a b o u t 1.$ g. ). The Eggs have seen a total of 285 eggs n 83 nests from northern Oklahoma to central Goahula, Mexco, and all have been mmaculate whte. The egg s smlar to that of the Bell s vreo, but more pyrform. Bent gves the average j measurements for 50 black-capped vreo eggs as 1?.6 x 3. mrru wth extremes of 19»3 x 12.7, 18.8 x 4..7, 6.O x 12.7, and < X 12.2 mm. have measured only sx eggs and they fell : : wthn these measurements except for one whch measured 17.2 X 11.8 ram. ; The average weght of 21 one-day-old eggs from sx j dfferent females was 1.59 grams. The eggs lost weght! throughout ncubaton so that by hatchng tme they weghed! only 1.1 to 1.3 grams. Ths gradual weght-loss was about the same from day to day n artfcally ncubated eggs. t was rregular n the nests, suggestng that the habts of the brds and the weather may have affected t. A Bell s vreo jegg lost more weght durng ncubaton n a black-capped vreo nest than dd three black-capped vreo eggs n the same best, but lost less weght than dd three other eggs of the jsame clutch n the parent Bell s vreo nest. : A black-capped yreo egg lost less weght durng ncubaton than dd three ; Bell s vreo eggs n a Bell s vreo nest, but lost more we^t _ fchan dd three other eggs of the same clutch n the parent

41 28 b^larc^k-cappe 7±r80-Te-stT T ls -ffe rs T c ^ m a y ^ v e la r lr ln ; j ncubaton habts, n nest stuaton, or n the eggs (posshlv the porosty of the shell). Both transposed eggs hatched and the young were reared by the foster parents. ncubaton ncubaton begns wth the layng of the second or thrd egg. One female started ncubaton wth the second egg of a four-egg clutch, another wth the thrd egg of a three- egg clutch. Both of these were re-nestngs. From the se jquence of hatchng, t appears that ncubaton often starts! wth the second egg. Both sexes ncubate. The male lacks a defnte brood patch, though n a few ndvduals have notced a slght bareness n the abdomnal regon. The females have a large brood patch measurng about 1$ x 30 mm., whch becomes hghly vascularzed after four or fve days of ncubaton, and flaccd and yellow after eght or ten days of ncubaton, then returns to normal appearance. There seems to be consderable varaton n the condton of the brood patch, and ths varaton may depend on whether or not the brd has ncubated before and f so, for what perod. One female that was layng jshowed no brood patch, and another showed vascularzaton. have caught a female two days after her eggs had hatched, and she stll had a large, slghtly vascularzed, slghtly flac- pd brood patch.

42 29 r watched one neat for S "hours c ontîrïuously oh "the^ ; ; frst day after the clutch was completed (on the fourth day : j of ncubaton), and agan on the lljth day of ncubaton (two j days before hatchng), to see what occurred durng both the jearly and late stages of ncubaton. On both days, ncuba- ton was shared by the male and female, but snce the female Spent the nghts on the nest, she actually accomplshed about j two-thrds of the ncubaton. Tables and summarze the data obtaned.! : On the fourth day of ncubaton, the longest natten- :. j tve perod occurred n md-day (ll:lo-ll;30 a.m.) and was l. ^. mnutes n duraton. Attentve perods ran about 20-^0 mn- utes n the mornng and were longer n the afternoon. Durng, the cooler parts of the day, the brds sat deep n the nest, j but n the heat of the day they sat hgh, apparently thus ; varyng the temperature of the nest contents. Late n the afternoon the wnd arose, and the nest was jostled consder- 1 ably but the ncubatng brd sat tght. On the l.th day of ncubaton, the longest nattentve perod was 10 mnutes. Attentve perods were shorter than on the fourth day but total attentveness was slghtly more. ; The nest was left unattended for ^.7^ of the tme observed asl jcompared wth 11. on the fourth day. Part of ths dffer- ence may be accounted for by assumng that the brds were jmore dsturbed by my actvtes and by the blnd at frst [than they were later.

43 30 At ths nest and at others that have observed, there was a defnte pattern of behavor durng the changeover of brds at the nest. Usually the male sang a phrase or two of the "nest song" as he approached and the female repled wth a soft "shrade" and left the nest. On returnng the female agan gave a soft "shrade" and the male left, sngng a phrase or so as he went. Once n a whle he sang just before leavng, but such songs certanly can not be compared wth those gven by warblng vreos (Vreo glvus) on ther nests. One female that watched tendng a nest alone (the male was carng for the frst brood), anrwunced her approach to the young by an unmuscal phrase or two..vhle she was ncubatng, the male often came to the tree wth the frst brood and called her off the nest, and she left and returned wth a soft "shrade." Both brds roll the eggs from tme to tme wth ther blls whle sttng or just before settlng on them. The male apparently does not ncubate eggs of the second brood, beng occuped wth the care of the frst brood. n one case n whch have data on the second brood of a banded par, the female took another mate to help her wth the second brood; n another case the female undertook the task by herself. have observed other females (unbanded) carryng out ncubaton by themselves whle what took to be ther mates cared for young probably of the frst brood. Table summarzes observatons made of the female (above)

44 31 TABLE OBSERVATONS OF NEST (N2) ON FOURTH DAY OF NCUBATON Tme Mnutes Brd on Nest Male Female Mnutes Nest Unattended 5 :00-5 5: : :17-6 6:55-6 6:56-7 7: : : :37-8 : a.m ^ 35 3 ^ :43-9 9: : :45-10:18 10:18-10:23 10:23-11: :02-11:16 11:16-11: :30-12:00 noon :00-12:18 p.m... C 2 : 18-12: :31-12:42 12:42-1: :22-1:50 1:50-2:51 6' 2:51-3:31 3:31-4: :20-5:07 5:07-6: : 03-6:08 6:08-6:23 *6:23-6:37 6:37-7:10 *7:10-7:23 7 :23-8:00 Total Tme 4 H Number of Perods 10 Average Tme for a Perod 4l*l #Brd dsturbed by observer (stll on when observatons ceased.)

45 32...* TSBLE'T... OBSERVATONS OP NEST (N2) ON FOURTEENTH DAY OF NCUBATON Tme Mnutes Brd on Nest Male Female Mnutes Nest Unattended 5 :20-5 5: :5 5 -o ;6 :20-6 6:44-7 7:01-7 7:02-7 7: : :14-8 :8 :4l-8 #: :18-9 9:36-9 9: a.m,...(5:17 male ? 9:57-10:08 *10 10 O :& :09 1 : : : :20-3 3: : : :28-4 l 4 : W l r L Ï ^ _ % '24 25 ' frst noon p.m heard)

46 33 T ABLE" X C'on'tlnwd Tme Mnutes Brd on Nest Male Female Mnutes Nest Unattended :k6-k:56» ^:56-5:00 t 5 :00-5:01 1 5:0-5:lt 13 5:14-5: :17 5:22 5 5:22-5:45 23, 5:45-5:46 ; :46-6: :12-6: :51-6:52... l 5:52-7: :04-8:00 56 (Stll on when observatons ceased. jtotal Tme l ;Number of Perods {Average Tme for a Perod 21« ,8 j «-Brd dsturbed by observer. TABLE OBSERVATONS OP NEST (N4D: SECOND BROOD, NCUBATON ON THRD DAY BEFORE HATCHNG Tme Mnutes Brd on Nest (Female only) Mnutes Nest Unattended M ^ 6:12-6 &:53-7 7:o4-7 7 : ; 4 o :30-8 ^^35-9 Total, 25 a.m s (stll on nest when observatons ceased.)

47 3 4 ;tïïât n c ü B ^ a lïïïe brood alone. She left the nest unattended 18.8^ of the tme that watched t. She 'guarded the nest closely, never leavng ts vcnty. f jcould not see her and put my head out of the blnd, she mmedately scolded. ; ; The total ncubaton perod vares from 4. to 17 days. determned the ncubaton perod 3 tmes n Oklahoma and twce wth artfcal ncubaton. The longer per- ods occurred early n the season, and when nests were cowbrd parastzed. Most of the varaton probably can be explaned by varaton n the attentveness of the parent brds. Some! may be due to clmatc nfluences. Attentveness s lessened : jwhen a cowbrd egg hatches, but ths s not always the case, ' snce n two nests wth cowbrd chcks the vreo eggs hatched n lj. days. {the same day; n three nests, they hatched on dfferent days.! n one"nest, all eggs (four) hatched on the same day. ng occurred at any tme of day, and probably of nght. Hatchng The eggs usually hatch over a two-day perod, nd- jcatng that ncubaton s started before the clutch s com- jplete. n seven nests the second and thrd eggs hatched on Hatch- jhave seen eggs reman ppped for as long as 12 hours before patchng. The egg s ppped around ts greatest crcumfer- ence and the chck pushes and kcks out.

48 35 E^gsTêlTs are pr o^mptly^ thé he s t. At ohé nest, they were carred away wthn 15 mnutes after hatchng. At another nest watched the female remove them. She probed nto the nest whle perched on the rm, and fnally lfted ' the shell up over the rm. Both halves fell to the ground, land she flew down and scooped up one half and carred t off^ :She must have forgotten the other half, for t remaned where lt had fallen. One afternoon, found a marked half-shell :about 75 yards from the nest n whch the egg had hatched that mornng. t was lyng near the edge of the water where the vreos drank. Ths s the only observaton have as to j {where the shells may be taken when removed from the nest. jhave never seen the brds eat any shells. 1 have not seen the adults help the young out of the egg. Several tmes have found ppped eggs on the ground near the nest. t occurs to me that the nstnct to remove the shell may lead to removal of ppped eggs that are slow n hatchng. Ths may be benefcal, for the chcks that have trouble at hatchng may be weaklngs. The Newly-Hatched Chck At hatchng, the chck s naked and blnd. There s not a trace of down. The eyes can be seen clearly through the transparent skn, but the lds are not opened untl the {second day, and then they are only half opened. The skn s yellowsh pnk, as are the bll and feet. The gape s yellow

49 36 {and has ah upwardangle toward The eye.the body wall s! Transparent and the gut, lver, and other organs can be planly seen. A worm fed to the chck can be seen passng from the mouth to the stomach. The chck weghs about a gram at hatchng. The Development of the Young Brd The young gan approxmately a gram per day untl they wegh between seven and eght grams. Ther weght upon leavng the nest s about eght grams. The percentage n- crease n body weght s greatest on the frst day and dmn-l ; shes n a regular progresson thereafter. Graph shows growth curves for three chcks n one nest, and a theoretcal jcurve based on exactly 1 gram per day ncrease n body weght, j jtable V gves results obtaned from weghng nestlngs daly n three black-capped vreo nests and n two Bell s vreo nests. stopped weghng the chcks when they were sx and seven days old because handlng mght nduce them to fledge prematurely. Two black-capped vreo fledglngs out of the nest for one day and two days weghed 8.1 and 6.88 grams re-!! spectvely., n an attempt to determne ecologcal dfferences be-! : jtween Bell s and black-capped vreos, exchanged eggs be- Tween two nests of these speces. The eggs hatched and ob- served and compared the development of a black-capped vreo chck n a Bell s vreo nest wth two Bell s vreo chcks and

50 37 GRAPH GROWTH CURVES OF N2 BROOD 100 days after hatchng 1 s frst chck hatched, 2 second, and 3 thrd. Dotted lne shows theoretcal curve based on 1 gram per day ncrease n weght.

51 38 TABLE V... DALY WEGHTS OF NESTLNGS N GRAMS Age n Days Blackcapped Vreos N2 N2 N l.l ? n56 nb6 N$6 N3$ N3S N35 N3S * 2.SS ^% Ü Î 4.08 w ; 4. 8$ : ^ ! Bell's Vreos B1 B1 B1 B2 B2 B * ^ The frst column ndcates the clutch. the second the sequence n hatchng. Snce all nestlngs n a nest were [weghed at the same tme, varaton varaton n age. 1* Brd j 1 reared n foster nest. n weght often ndcates 1 1,

52 39 oî a Bell S"vlrëo chck n à he s "wth three hlack-câpped ^ vreo chcks. Graphs and V show daly weghts of the nestlngs. had hoped to repeat ths experment wth the whte-eyed vreo, but was prevented by predaton and cowbrd parastsm. Both adopted chcks grew farly well, though the black-capped chck dd not do as well as ts sblngs or ts ; nestmates. : The chcks of the black-capped and Bell s vreos are ; very much alke, nether havng down at brth. The head shape s dfferent, that of the black-capped vreo beng the rounder as seen from above. The gape of the black-capped vreo at an age of one to four dajs s yellower, and the tp ; lof the bll darker. The tp of the bll n Bell s vreo does not become dark untl the ffth or sxth day. As soon as the wngbars become evdent at the age of three days the defnte; yellowsh wngbars of the black-capped vreo are dstnctve.! Prom then on the plumage patterns make t easy to tell the! two apart. Both have a "shref" call, but that of the black- happed vreo s hgher n ptch, On the day of hatchng, tny blacksh feather buds jean be seen along the outer edge of the manus and the dstal ' jhalf of the forearm. No other feather buds are vsble. By ^ ^orn of the second day a small porton of the md-dorsal ; tract shows, but no qulls break through the skn untl the thrd day. Feather buds are then vsble on the captal and! ventral tracts. On the latter they are hard to see bep_au_sje

53 40 GRAPH DALY WEGHTS OF MXED BROOD N BLACK-CAPPED VREO NEST age n days (2 ), (3 )> and (j.) represent black-capped vreo chcks, 3 a Bell's vreo chck from nest Bl. All were reared n black-capped vreo nest N3$. (2) and (3) hatched June 26, (j.) hatched June 27, and 3 hatched June fell out of nest and ded on fourth day.

54 41 GRAPH V DALY WEGHTS OF MXED BROOD N BELL'S VREO NEST 10- age n days (1) and (2) represent Bell's vreo chcks, 1 a black- capped vreo chck from nest N3$. All were reared n Bell's vreo nest Bl. (1) hatched early June 2^, (2) on June 26, and 1 late June 2^.

55 42 6T ther lght color. Oh the fourthhay the prmaryhuhs ex^ tend about l/j- nch, l/2 nch on the ffth day, and about 3/4 nch on the seventh day. On the eghth day, the feathers un- sheath, except for those of the crown. These unsheath on the nnth day. By the tenth day, the young are farly well feathered, and the prmares are about half unsheathed. On the eleventh day the prmares are about 3/4 unsheathed, and there may stll be a few blood qulls at the base of the bll; The young keep ther eyes closed most of the tme untl they are fve days old. They grasp the bottom of the nest wth ther feet and are dffcult to dslodge when only a few days old. On the sxth day they show fear when handled^ and are able to st on a perch. f unduly dsturbed they may leave the nest as early as the tenth day. 'Usually they leave the nest on the 11th or 12th day. Normal departure occurred, ' n two nests on the 1 0 th day, n four on the 1 1 th day, n three on the 12th day, and n one on the 13th day. n the last case, the sole juvenle n the nest was retarded n ts development, featherng out on the 1 2th day. j Nest-leavng s staggered. Qute often t begns at sundown. One fledglng hops out of the nest and sts on the branch besde the nest for the nght. The followng dawn, the remander leave the nest. The fledglngs stay near the : nest for a few days. Often they seek shelter n cedars where; jwere t not for ther calls, they would be nearly mpossble : :to locate. They call almost constantly for the frst day or

56 ' 1^3 so, thus mantanng contact wth the adults. As the young become more adept at flyng, the famly moves about ts terrtory. n the Gogar study area, famles moved from the nest-slopes down nto the shaded ravne where there was water. also saw some Texas famles move from, the hllsdes down nto more heavly, wooded, though dry, stream beds. Generally the famly remans on or near ts terrtory untl mgraton, though t sometmes wanders nto neghborng terrtores or even farther. Ths s probably because the juvenles are not aware of terrtory and the ;adults follow them. watched one fledglng for j]. days after t had left the nest. At noon on the day t left the nest, found t jsttng seven feet up n a cedar about 70 feet from the nest. 0n the second day t was sttng about 12 feet up n an oak j ; some 120 feet from the nest, havng moved about $0 feet. t ; could fly, and we caught t only wth some effort. When re- jleased, t flew 60 feet. ts landngs were sometmes awkward. For the next 25 days, was able to fnd the male and! the juvenle wthn 100 yards of the nest. dd not see the female n attendance after the fourth day (June 16). On ljune 21, found her wth a neghborng male workng on a half-fnshed nest. She had left her frst mate who was car-! ;ng for ther sngle fledglng. On the ^]rd day after the young brd had left the nest, the male parent was observed to^ : fly at hs offsprng n a hostle manner, t r yng to dscourage

57 44 t from followng hm and from beggng. He even appeared to ; be tryng to escape from t. The followng mornng, found the young brd alone, lt was followng a small flock of chckadees and gnatcatchers about on the terrtory. t scolded wth a hgh-ptched "shrade," as t had been dong snce fve days after t left the nest. Then t sang a squeaky song that remnded me some- :what of that of the rusty blackbrd (Buphagus carolnus). heard the parent male sngng n another part of the terr- ' tory a lttle later n the mornng. He no longer scolded me as he had when attendng the juvenle. So at days after ; 'fledgng, ths one young brd was apparently completely n- dependent of ts parents. watched the development and postjuvenal molt n a brd that made captve on the day t left the nest. t 1 ' ; took two days for the captve to adjust to captvty, after whch t flew toward me beggng whenever entered the room n whch t was kept. For the frst few days t called shref" every few mnutes. Later t called nfrequently, presumably only when hungry. At roostng tme t gave a j "chrruup" note, whch t also gave upon awakng, but at no! other tme. t gave small "kek" notes when a dog entered the! room. When t was 2. days old, t gave the typcal "shrade" scold note of the adulfc for the frst tme. At 12 days t could preen effcently. At 1^ days t; could fly well. On ts 17 th ^ y t at tempt ec to take food

58 from the forceps Wth Whch fed" t nstead of merely open- ^ ng ts mouth. Two days later t made ts frst attempts to fnd food for tself. t begged "at, then pcked up, a larva placed besde t. t made bathng motons for the frst [tme at the age of 2)4. days. When t was 28 days old, t caught [apart. slow. nsects and held them wth ts feet whle peckng them t was not very effcent at catchng prey, beng too At ths age t snapped ts bll and attempted to bte when handled. At roostng tme t flew to me, perchng on ray head. Prom the age of 10 days.(nest-leavng), t slept n the typcal adult poston. The weght of the captve ncreased gradually from ;7 to 9*7 grams, ts weght on ts 22nd day. The legs had be-' jcome notceably blue by ts 19th day. The rectrces grew [from about 3 mm. at nest-leavng (10 days old) to 28 ram. at ;! j * j 2). days age. When the brd was 32 days old, the sheath-free ; rectrces were 38 mm. n length. notced the frst sgns of the postjuvenal molt two or three greensh feathers n the md-dorsum when the j brd was 21}. days old. At 28 days, the aurculars were molt- : [ng. At 30 days the molt showed on the nape and occput, the ncomng feathers beng darker and about a thrd longer than those of the juvenal plumage. The greensh frst wnter plumage formed a V across the back. Brght yellow axllars ; began to appear. The followng day the tps of a few buffy feathers appeared on the breast. At 32 days of age, the loreé

59 46 am efè rng were moldng, anst ïîïe'lower^hërrôt" ÇKê ' t ^ E was : n frst wnter plumage. When the brd was 37 days old, huffy frst wnter feathers formed an nverted-v from the md-lne down the lat4 eral tracts of the breast to the level of the second wngbarj The underlnng of the wng had been replaced. The chn was moltng. New feathers were comng n on the thghs. The head molt had proceeded from the forehead backward to the j level of the eye. The dorsal plumage was about two-thrds replaced, the upper porton stll beng juvenal. At about ths tme the molt, whch had been progressng rapdly, slowed, probably because of unfavorable envronmental cond- ; tens. When the brd ded accdentally at the age of $0 days^ t was found to have been a female. Care of the Young Wthn a few hours after hatchng, the male begns tc brng food for the chck(s). Snce he shares ncubaton, there s no queston as to how he becomes nformed of the bvent. t appears that as soon as a chck can rear ts head and beg, ths acton serves as a releaser for the parent jbrds to begn feedng t. As soon as the male begns feed lng, he ceases ncubatng and broodng. Actually, what ltjtle broodng he does s probably carred over from ncubaton before he changes hs routne, for have never seen any of the males n the nest after all the eggs have hatched.

60 kl although they dd spend tme stanhlhg oh thé nest rm dr m - ; sde t, guardng and shadng the young. The chcks are brooded by the female durng the cooler portons of the day, and at nght untl they are seven days old. Durng the warmer part of the day, she may st hgh upon the nest or stand on the rm. As the chcks grow, : the adults spend less tme at the nest and more tme gettng f food. At nest Nlj. the male spent 327 mnutes of hs 868 mnute day (he was frst heard at ^:20 a.m. and last seen at 7 :j.8 p.m.), or approxmately 3 7 «6/o of hs tme, standng be- Ade, guardng, or shadng the young on the frst, day after ; hatchng. Hs longest guardng perod was 6$ mnutes, the ^shortest two, the average lf. The female spent a total of l79 mnutes broodng durng the day and was on the nest at ; hght (7:10 p.m. to ^:10 a.m.). Her longest daytme broodng perod was 62 mnutes (6:^1 to 7:53 a.m.). After 10:00 a.m.,; jshe dd not brood agan untl nght. Besdes broodng, she jspent l60 mnutes guardng (longest perod 55 mnutes;. ^shortest one mnute ; average l6 mnutes). The longest perod that the male was absent from the nest was 1^7 mnutes (6 :3^! 1 to 7:21 p.m.). ; The female was absent once for 83 mnutes! (f:38 to 6:00 p.m.). The male spent 118 mnutes guardng, ' o jthe female, 3 8. The longest guardng perod of the male was ; 39 mnutes, of the female 3 0.! f the female s at the nest, the male gves the food he brngs to her to feed to the young; f she s away, he

61 48 feeds them. Male's pfdvtded^r^hly t of thë""îood for the young. On the day of hatchng of the last chck at one nest, the male made 77 (7 9 *3%) trps to the nest wth food and the female, 20 (20.6%) trps. Feedng was neffec-; tve (..l% of the tme, for although food was brought 97 tme% feedng was accomplshed only 93 tmes. Twce the female atq the food, once she dropped and lost t, and once the male ate t. The male fed the joung hmself j.0 (5l.9%) tmes, and gave food for them to the female 37 tmes. On the eghth day at ths same nest, the male brought 73*0% of the provender, the female 26.9%. On the tenth day, he brought food 6. (6 8.8%) tmes, whle the female brought t 29 (31.1%) tmes. On the latter day he gave the food to the! female only twelve (18.7%) tmes. Once she begged for food jhe had brought but he gnored her and fed a nestlng whle : she stood by. No feedngs were neffectve on the eghth or tenth days. At nest N13, whch held a cowbrd chck, the male! 'brought 75% of the food on the second day, 7 0 *4% on the fourth day, and 65*3% on the ffth day. On the second day he gave the food to the female 3 6.6% of the tme. On the other 1 days he dd not gve her any. Presumably because ths par! had dffculty n satsfyng the demands of the cowbrd chckj, the female was seldom at the nest when the male arrved wth ' food. t seems that as the female spends less tme broodng/ she spends more tme gettng food for the chcks. Broodng

62 k9 ceased on the ffth day at he at 313 -(the female 'was hot dh '; the nest the fourth nght). ; n feedng, the food s crushed n the mandbles, and arranged parallel to the bll before t s fed. Usually only one tem at a tme s brought; however, dd observe one male that brought several small tems at a tme several tmes on the frst day. The female accepts food from the male wth her mandbles wde open, pecularly so, as f ths acton ware a releaser to nduce the male to turn the food over to her. Nce (1929) descrbes ths acton n Bell's vreos. n fact, the behavor of the two speces at the nest s very much alke. Wheelock (190^) mentons regurgtatve feedng n vreos. Ths have never seen n the black-capped vreo. f t occurs at all, t must be unusual. Lawrence (19h3) and (Stephens (1918) dd not wtness t n the red-eyed vreo j! ( Vreo olvaceus). Nce (1929) once saw a female Bell's vr-j!! leo swallow food, then pass t to the young four mnutes later! There appeared to be no set rhythm n feedng the young. Some brds fed steadly, others dd not. Generally j (there s a peak n feedng of chcks n early mornng and late afternoon, probably a counter-balancng of the effects ^!of nght metabolsm wthout food. Before the early and after; (the late peak the adults must feed themselves for the nght.! Graph V depcts the feedng of four young at nest Nl[[ on (! bher frst and tenth days. The_number of feedngs on both

63 $0 GRAPH V FEEDNG RATES N A NEST WTH FOUR BLACK-CAPPED VREO CHCKS s age n days The number 1 (tme) stands for the frst hour of observaton, $:00 to 6:00 a.m.; number 2 stands for the hour 6:00 to 7:00 a.m., etc. The sold lne shows feedng rates on the frst day (chcks -12 to 2[.+ hours old); the dotted lne shows them (same brood) on the tenth day. The peak of feedng actvty on the frst day came between 5:00 and 6:00 p.m. On the tenth day, t occurred between 11:00 and 12: 00 noon.

64 5 1 days was the same "('93 ),'hut ^ m c h "larger tems were hrhught-tcj the young on the tenth day. Data from three nests whch held two, three, and four chcks respectvely, and covered dffer-j ; ent ages of these chcks from less than 12 hours to 9 days, revealed that the average number of feedngs per chck per hour vared from 0.8 to 2.6, That s, at the peak of feedng durng the day, a chck may receve three feedngs per hour, and at the low pont t may receve less than one feedng per hour. The most rapd feedng rate observed was at nest N13 1 Contanng a cowbrd chck, whch was beng fed at an averagd rate of feedngs per hour on ts fourth day> and of 13 feedngs per hour on ts ffth day. At the end of the ffth day the chck weghed l8..0 grams, just a lttle less than four vreo chcks of the same age would have weghed. f ths feedng rate s dvded by four, then t compares wth {the rate per vreo chck per hour n other nests. Durng the nestlng perod the male and female contnue to announce ther arrval at the nest as they do durng ;ncubaton. The male nearly always sngs a phrase or two of the nest song as he comes to the nest, and the female scolds softly as she arrves and leaves. At frst the young respond only to vbraton of the nest, but as they grow older, they! respond to the sgnals of the approachng adults. t was hard to ascertan that the chcks responded, but could see ther heads above the nest rm at seven to eght days and they responded at that age. A cowbrd chck responded to thg

65 52 sounds of the adult' vlreos ah ^ days... "' A vreo, carng for her second brood unaded by the male, was very quet on the second day after the young hatched, although she scolded softly sometmes as she left or arrved, as she had when ncubatng. On the sxth day, how- j ever, she gave rather squeaky mtatons of the male nest song as she arrved. Ths suggested to me that announcng ; arrval at the nest s more than a sgnal between the adults* : t appears to be a means of keepng the famly together afte fledgng, and ths female seemed to be preparng to assume ths task. After each feedng, the adult brd looks for fecal ' sacs whch appear to be normally dscharged only at ths tme. The nest s kept clean untl the chcks leave, at whch tme the last few droppngs may reman about or n the nest. The fecal sacs are usually carred more than 1$ feet from the j nest before they are dropped. The sacs are eaten by the adults durng the frst fve days of the chcks' lves; from the ffth day on they are carred away. A par carng for a cowbrd chck began carryng away sacs on the second day, but ate about half of them. On the thrd day they carred t allj away. Perhaps the sze of the fecal sacs determnes when th^ adults no longer eat them. At a nest of four small chcks, excreta are removed about once an hour (average rate for e n -!! tre day), and about a thrd agan as often when they are older. Male and female shared ths duty evenly on the frstj

66 ' 53 day at nesï On ïkè eîgïtlt ard tete days tde male dar- j red away two fecal sacs for every one removed by the female! The nests are kept clean not only of excreta and egg4 shells but also of other debrs. Ths ncludes dead chcks, f these are small enough for the adults to lft. The ds- appearance of small vreos n nests wth cowbrd chcks puz- zled me untl observed one nest contnuously from the hatchng untl the chcks were gone. Cowbrd eggs are usu- ally deposted n the nest before the vreo clutch s completed. The cowbrd egg hatches two to four days before the vreo eggs (12 day ncubaton perod for the cowbrd n black-capped vreo nests) and by the tme the young vreos hatch, the cowbrd outweghs each of them more than ten tmes; n one nest, a three-day-old cowbrd weghed grams whle ts nest mate, a newly hatched vreo, weghed 0.86 grams (see Fgure 1). The cowbrd s able to rase ts head up far above the vreo n beggng, and gets most of the food. The Cowbrd requres about as much food as four vreo chcks so t s hungry and begs most of the tme. The vreo chck gets scarcely any food, and s trampled and crushed by ts parastc nestmate. After a day or two, the vreo chck des and ts body s removed. j watched a female vreo remove the bodes of two two-day-old chcks one mornng. They had ded because of the; j presence of a cowbrd chck. She brought food to the cowbrd,; then, after feedng t, she began workng n the nest. After

67 ! üe âa-cec%-ôür-ââa flew away wth t n her bll. She came back, fed the cow- brd, and removed the other dead chck. These chcks must! have weghed between one and two grams, so she carred be- tween one tenth and one ffth of her own weght. Stephens (1918) placed certan foregn objects n the nest of a red-eyed vreo and found that the brds removed them. dd not experment wth the black-capped vreo. An ncubatng female deserted a much-ncubated clutch of eggs because a leaf fell n the nest and covered the eggs. n janother nest, a young brd ded on ts nnth day. t was evdently too large to be removed by the adult. The other. chcks n the nest fledged as nspected the dead nestlng. t s well that they dd, for n a short whle the nest was over-run by ants. The young are actvely defended by the adults who threaten, pounce, and snap ther blls at ntruders. They also warn the young of danger. have never observed njury tbgnng. n general they gnore other speces of brds, but have seen female vreos ntmdate female cowbrds by as- burnng a crouchng poston and openng the mandbles wde. once saw a female vreo behave ths way toward a feld bparrow (Spzella puslla) that happened to startle her on the nest. All adults scolded every tme they saw me near [ther nests, but they were partcularly excted about nest- leavng tme.

68 f j. ' ^r- --. «. '# -m* ' - - '- V....m. -,. Two males of doutle-brooded pars drought frst broods to the vcnty of the nest whle the female was ncur batng the second clutch and carng for the second brood, bull never saw the male or juvenle brds go to the nest. There was no evdence of nest helpers. f the female does not re- mate for the second brood, she assumes complete responsbl- ty for t up to the tme of fledgng. Nestng Success and Losses Much of the black-capped vreo*s reproductve effort s unsuccessful. Prom 2).3 eggs of whch kept record, only j j.3 chcks that lved to the age of fledgng were produced. n other words, 17*6^ of the eggs were successful to ths da-* ; j gree. Kendegh (1 9 ^2 ) gves data on nestng success for nne : speces of brds buldng elevated, cupped nests, and the! percentage of eggs that produced fledged young ran from 29 (wood thrush, Hylocchla mustelna) to $8 (cardnal, Rchmondena cardnals). The average percentage of eggs of l6 speces (ncludng cavty-nestng brds such as the house wren (Troglodytes aedon) that produced fledged young was lj.2.7, Putnam (19^9) found that of 21^.5 eggs of the cedar waxwng j (Bombycla cedrorum), 6 9.8^ produced fledglngs. Nce (1937) consdered a 23^ success of the song sparrow (Melospza melodla) as very low. She consdered the.0 to 4.6 per cent success reported n eleven studes by varous nvestgators as the usual rate for open nests of passernes n the North

69 56 Temperate Zone. have found only a few nestng success fgures for other speces of vreos. Lawrence (1953) reported that of 96 eggs n 30 nests of the red-eyed vreo, 59 produced fledged young, a success of 60^, Ely (1957) found that only one of llj. Bell s vreo nests produced young (9.1^ of the eggs produced fledglngs). Ptelka and Koestner (19^2 ) reported that of 26 nests of the Bell s vreo, fve were successful, a success of 19^. Countng any nest successful f t produces one vreo fledglng, of?6 black-capped vreo nests l5 were successful, a nest success of 1 9.7^, a fgure comparable to that of the last-named study. Tables V, V and V gve data concernng the causes of nest loss. Loss of eggs before hatchng amounted to 55*1^ of all eggs lad. Of ths loss {13k eggs n all), attrbute 72,3% (97 eggs) to cowbrd actvty. Ths ncludes beak-gouged eggs found under and n nests, eggs whch dsappeared one at a tme wth subsequent layng.of cowbrd eggs, and eggs deserted because of cowbrds. Ptelka and Koestner ( ) estmate that 17 of 26 Bell's vreo nests were unsuccessful because of cowbrds (four nests faled for other reasons). Ely ( ) found that 10 of 3 Bell s vreo nests were parastzed, and that only one parastzed nest was successful (the cowbrd egg n ths nest dd not hatch). Davd P. Parmelee ascertaned that 12 of 22 Bell s vreo nests at Norman, Oklahoma, n 1954* were parastzed. My own

70 57 T A B L E V ANALYSS OP NESTNG SUCCESS FOR THREE YEARS! Year Totals j Localty Okla. Okla Texas Okla. Nests started Nests lad n Eggs lad Eggs lost (See Tables V and V) Eggs deserted Eggs fully ncubated Eggs nfertle or addled Eggs hatched Chcks lost at hatchng 'Chcks lost to predators Chcks lost because of presence of cowbrd chck Chcks that ded n nest 2 2 Chcks fledged Nests successful n!fledgng young Pars successful n rearng at least one chck Number of pars observed

71 58 ~.. ANALYSS OF EGG LOSS Egg loss before hatchng Egg loss due to cowbrds Number 3k 97 Percentage! 55.1 of eggs lad of those lost' Eggs destroyed Eggs deserted 6? 30 Human nterference Predaton by mammals Predaton (snake) Deserton of those lost.4 of those lost; 7.{. of those lost; 5. 2 of those lost! TABLE V ANALYSS OF LOSS OF NCUBATED EGGS AND NESTLNGS Number Percentage Eggs fully ncubated nfertle and addled eggs O of eggs lad Chcks that ded n hatchng 9 Chcks ded 2 [Chcks lost to predators of fully ncubated eggs 19.0 of vable chcks Chcks ded because of presence [of cowbrd chck 2^ of vable chcks

72 59 lobservatons of fîër^-s vîbeô'tn Ü OklâbbmâT àtsbl ndcate great losses of eggs and young because of cowbrds. Eghteen black-capped vreo eggs (13, fo) of those lost, were deserted because of my actvtes. learned to be more dscreet after the frst season, and the loss was reduced from 10 eggs (three clutches) the frst season to one egg (an ncompleted clutch) n do not beleve that :my actvtes caused any more losses to predators than there would have been had not been present. probably frghtened away as many predators approachng nests as led to nests. And n no nest near a blnd erected for daly observaton was there any loss as long as the blnd was present. Two eggs were lost to a fox squrrel (Scurus nger)j jthe only case of mammalan predaton whch observed. Ten leggs were lost to other predators, very lkely snakes. En- [tre clutches dsappeared wthout a trace of dsturbance about the nest, and ths would suggest predaton by snakes. Snakes were numerous n the area, and caught a plot black- jsnake (Blaphe obsoleta) n the act of swallowng a nestful of young vreos. One clutch of four was deserted when a leaf fell nto the nest (see p. 54) * Three eggs that were de- jserted were the fourth clutch of a par of vreos that had already deserted three clutches as a result of cowbrd para- stsm. Eghty-four vable chcks were produced from~109 fully ncubated eggs. nfertle and addled eggs and chcks!

73 6o whch ded a: hatëîhg Totalled 2]. remoedreproductve-vgor-loss were two chcks whch ded unaccountably as nestlngs. One chck ded at the age of nne days, the other on ts thrd day. Most losses occurred at the begnnng and at the end of the breedng season, ndcatng that loss of reproductve vgor probably les n reduced "breedng drve or ncentve" and declne of optmum weather. Kendegh (19f2) has shown that the percentage of success n the house wren correlates wth the mean temperature of the perod n whch the eggs are lad. Reduced-breedng-drve s also reflected n the number of nests abandoned before completon. Four of sx nests represented frst nestng attempts, one was a late attempt, and one a second nestng. One other early nest was completed [but found no evdence that eggs were deposted n t. t [s possble that the eggs were removed by cowbrds before jvsted t. j Durng the nestlng perod, as durng layng, the chef loss was due to cowbrd parastsm. n all cases n jwhch a cowbrd chck occuped the nest, no vreo chcks sur vved. Nestlng predaton was, n nearly every case, be- jleve, by snakes. n 1956, n Oklahoma, three seven-day-old jchcks n one nest were eaten alve by ants (Crematogaster sp.).! Toward the end of each breedng season, surveyed the study areas and adjacent areas, and observed whether or

74 6 hot the adults were" X n at'tend'ahc^^... Shde mdst 1 : { early nestngs were unsuccessful, few juvenle brds were n-1 : j dependent of the adults by late July and early August. Ths survey served as another check on how successful the brds ^ had been n rearng young. Of a total of 77 pars surveyed, (^9 *7%) were successful n fledgng at least one young brd by the end of the breedng season (see foot of Table V). ;! Fall Mgraton The young brds dsappear from the breedng grounds frst. They are followed by the adult females, then by the adult males, some of whch reman longer than others. Fall departure appears to be less precptous than sprng arrval. The speces has been recorded n Nayart, Mexco, as early as August 27. A specmen (MC:OC) taken on that date was a fe- male. My latest central Texas date for a female n 1955 was August 28 (one brd, Kerrvlle). Ths must have been about the date of departure for the females of that area that year, for looked for one every day for a month thereafter, but saw none. The last female seen at San Angelo, Texas, n 188^ was seen September 6 (Cooke, 1888). The last female seen n my Oklahoma study area n 195^ was seen September 9 (one brd). As for males, my latest central Texas date for 1955 j was September 11 (three seen. Hays County). The last male j seen at San Angelo, Texas, n l88 was seen September 25!

75 (Cooke, 1888 ). 62 TEe last male seen : n 19$^ was seen September 17 (one brd). Survval n 195^, banded 2l\. breedng adults (12 pars) n the Oklahoma study area. n 195^ found nne of the banded ' males and fve of the banded females ( ^ 1. 6 ^ ) n the j same area. One female banded n 19S^ dd not see n 195^! but dd fnd n 19^6. So 1$ (62.^^) of 2J4 brds are known to have survved for one year. n 19^5 banded fve adult males and nne adult fa- : males. Of these, four males and three females returned n j , an 8Q^ return for males, 33«3^ for females, $ Q p/o for both sexes., n , nne males and fve females, l. {^Ofo) of the ;28 brds known to be n the area at the end of the 1955 seals on, returned. Brds returnng for a thrd season (1956) ncluded jfve males and two females, seven (2 9.1^) of the 24. brds banded n 1954 Thus from data obtaned durng three years of observaton, l].l,bfo of the males and l6.6^ of the females jwere three years old or older; 33»3^ (males) and 25^ (fe- 1! males), two years old or older; and 2% (males) and 58.3# (females), one year old or older brds that had just entered the area. Theoretcally, f the percentage survval of a speces breedng at one year of age s 75, 25 percent of the!

76 63 populaton wll be made up of brds one year of age, 19 percent of brds two years old, and $6 percent of brds three years old or older, wth one brd n a 100 lvng to be 13 years old. Usng Brktt s formula n modfed form (Hann, 191+8) for calculatng average age, that of a male Vreo atrcapllus n the study area s estmated to be four to fve years (survval rate, 75 to 80^), of a female, one-and-a-half to two years (survval rate, 33*3 to +1.6^). have not had any returns on banded fledglngs, but ths s not surprsng for banded only 30. Brds n ther frst breedng season probably have lttle chance to breed n the area n whch they were reared because the older brds reman n, and defend, ther own terrtores. Of 13 males and 10 females caught n , only one par were frst year brds (8.6^). The sex rato for the Oklahoma study area n 1954 appeared to be 1 0 Ô males to 100 females; n » ;1 0 0 ; and n the Texas study area n 1956, 131:100. Stewart and Aldrch (1951) found dfferences n sex rato n vreos of other speces were hgh. Nce (1937) observed that female "survval" was two thrds to three fourths that of males n the song sparrow and that the sex rato was a lttle greater on the male sde. The dfference n returns for females (n ths study 55.5# (195S and 4 l.6# ( ) of those for males) may be explaned by ther elusveness and lack of attachment

77 64 t o'ther terrtores«'

78 CHAPTER V HABTS The habts of ths vreo are much lke those of other vreos, especally the whte-eyed and Bell's vreos. The black-capped vreo appears to be the most actve of all jvreos. Although not especally shy, t s dffcult to see land to keep n vew. The female, whch s especally dffcult to follow, s seldom seen except near the nest or young flfhen excted, the males often flck ther wngs open and shut quckly. scold. When alarmed, adults snap ther blls as well as Sutton (Peterson, 19-7) mentons the habt of hangng; head downward for an nstant before "dvng to a lower branch. The speces s not as responsve to "squeakng" as are many other brds. t bathes whenever water s avalable. Sun-bathng and dust-bathng were not observed. From vtoat have observed, beleve that adult black-capped vreos roost soltarly. When there are fledglngs, the famly may roost n the same tree. They generally roost near the top of the tree and the only trees have seer, jthem go nto were cedars. However, have made few 65

79 Broodt 66 (Observâtons at dusïc and tbey 'pr obably "a sd^" "rdb^^ Roosts appear to vary from nght to nght but are n the samd general area, and are usually not far from the nests. ng or ncubatng females spend the nght on the nests, sleepng wth the head turned back over the shoulder and the bll tucked under the tertals. My captve brd slept n ths manner also. The male black-capped vreo sngs at all seasons; however, the greatest amount of sngng occurs n the early j part of the breedng season. have heard males sngng n December on the wnterng grounds, though t was only a burst or two n the mornng and usually occurred when two males met each other. Accordng to such observatons as could make, j do not beleve that males have establshed terrtores n wnter, but rather that the sght of another male stmulates sngng. The song has been lkened to that of the followng jbrds: whte-eyed vreo. Bell's vreo, wood thrush (Hyloclfhd mustelna), mockngbrd (Mmus polyglottes), towhee (Pplo 1 jerythophthalmus ), and yellow-breasted chat (ctera vrens). thought t resembled that of the blue-gray gnatcatcher (Poloptla caerulea)«t seems to be more vared than that of any other vreo n the Unted States. t s qute long, lncludes some defnte mmckng, and yet t s pecular to the speces. Nce (1931) gves a detaled account of the l802g _ m d J.ts phrasng.^^^ a.j

80 67 complete set of plruws) of lïthays-coqfrtyt j Texas, and found that he gave 82 n fve mnutes. Ths was : at the heght of hs sngng. Each brd has ts own phrases, and ndvduals can bé dstngushed from song alone. There are at least four df-l ferent types of songs. The "announcement" song, gven on ar4 jrval, announces the presence of the snger to other brds. :Ths s the song usually descrbed. The "courtshp" song s gven when the male s courtng the female. t s a rapd seres of the phrases used n the announcement song, run softly together n a low, bubblng torrent. The "nestng" song s a short phrase or two gven when the male goes to thé nest or approaches the fledglngs wth food. The "terrtoral" song s gven when two males are dsputng possessons. t s very smlar to the courtshp song. have leard the whte-eyed vreo also gve such "courtshp" songs. When sngng the announcement song, the male sts uprght on one of the hghest perches n hs terrtory. When sngng the courtshp song, however, he s often on a farly low perch, near the female whch he s followng about. pave heard a female gve nestng songs when she came to feed nestlngs she was rearng by herself. have never heard any other "song" from females. Young males begn sngng n late summer, and snce they resemble females n plumage, ths may have led to the statement that the female sngs (Lloyd, 1807). 1 [The male never sngs on the nest as the warblng v reo does

81 68 fsèè page 30 j.... The black-capped vreo s not an early rser. heard songs of the black and whte warbler (Mnotlta v a r a), feld sparrow (Spzella puslla), cardnal (Rchmondena cardnal s), yellow-blled cuckoo (Coccyzus amercanus), panted buntng (Passerna crs), and Bewck's wren (Thryomanes bewck) before heard the black-capped vreo. n June n Oklahoma, the black-capped vreo s frst heard at about ^:5^-5:10 a.m. Other sounds made by the adults are scoldng and worry or protest notes. The typcal scold note s a sngle, harsh, low " shraade," whch sounds somethng lke the scold note of the Bewck's wren. The scold note of the male s slghtly hgher n ptch than that of the female, and that o:^ the young brd s stll hgher. A double note, "shad-dt," {s gven when the brds are especally excted. A worry or {protest note, a small, squeakng "tnct, "tsk," or " kek," s gven when the brds are only slghtly dsturbed. The scold note gven by one male to another s dfferent from that [gven when the speces s scoldng some other anmal. The lyoung make beggng noses, and have a dstnctve call note, f'shref, gven to nform the parent brds of ther where- jabouts. A note gven by the young Bell's vreo s smlar, {but slghtly lower n ptch. A fledglng black-capped vreo [reared from the egg by Bell's vreos n an area well removed {from black-capped vreos, gave calls a n ^ scold notes typcal

82 69 lof vreo atrcàflllüs. m v e r heard t sng."-.. ] My captve young brd gave a dstnctve "chrrup" when gong to roost and upon awakenng, but at no other tlme

83 CHAPTER V POOD AND FEEDNG The black-capped vreo, an arboreal speces, rarely leaves the trees and shrubs of ts doman. t feeds manly n the upper strata of ths vegetaton, gleanng nsects that lve on trees, especally oaks. have never seen t feed on the ground. The bulk of ts food s larvae, and most of these are Lepdoptera. have seen t eatng small butterfles (Perdae) and once, a large dragon-fly (Odonata, Aeschndae). The young, when small, are fed manly small larvae, sometmes spders, and small fles. As they grow, the tems fed to them are larger; bgger larvae and such tems as small grasshoppers and katydds are brought. As much as a thrd of ther food may consst of orthopterans. Tables V and X present an analyss of stomach contents from eleven black-capped vreos. All these specmens were collected between the hours of eght and ten n the mornng. Two were taken n the northern part of the breedng range (Oklahoma), three n the central (Texas), three n the southern (Coahula, Mexco), and three on the wnterng 70

84 f TABLE V ANALYSS OP STOMACH CONTENTS Knd of Food Stomach Number Anmal Matter; Arachnda Araneda 1 3+ Chlopoda nsecta Undentfed order Orthoptera (1) Tettgondae 1 Locustdae Neuroptera (2) Odonata (3) Ansoptera 1 Zygoptera 1 Hemptera (j.) Undentfed famly Phymatdae Pentatomdae Homoptera (5) Undentfed famly Ccadelldae Fulgordae 2 1 Coleoptera (6) Undentfed famly Buprestdae Clerdae Phalacrdae Coccnelldae Coccnella Chrysomeldae 1 1 Pachybrachys Cryptocephalus 1? Curculondae 1? 1 1 1?

85 72 TABLE 'V C ont rrde d Knd of Food stomach Number S Lepdoptera (7) 1 Undentfed famly adults larvae Notodontdae (larvae) 2 1 Hesperdae (larvae) 1 Phalaendae (larvae) 1 1 Pseudoleta 1 Dptera (8) ; Undentfed famly Vegetable Matter: ;Seeds Undentfed 2 1 Legumnosae 1 Compostae l Î! Stomach Number Localty Date 1 Caddo Co., Oklahoma September 9» 1934 : 2 Nayart, Mexco December 28, Nayart, Mexco December 29, 1935 h Coahula, Mexco June 17, Hays Co., Texas July 9, Knney Co., Texas July 13, Uvalde Co., Texas July 12, 1956 : 8 Caddo Co., Oklahoma September % Snaloa, Mexco December 21, Coahula, Mexco June l8, Coahula, Mexco June 1 8, Î5- Numbered for use n Table X. f Number of ndvduals found.

86 73 "... 'TABCETnC FOOD OF BLACK-GAPPED VREO Stomach! No. Knd of Food Estmated Percentage of Bulk of Total Vegetable Matter Spders Centpedes Anmal Matter nvertebrates Orders nsects Contents (see Table V) k j! o k ko 50 a : c 10! ll o ko!

87 7 grounds (Snaloa and Nayart, Mexco). The sample s much too small to gve a complete pcture of the food habts, but t does suggest that ths vreo s not unlke other vreos n ts feedng habts. Bunker (9 O) suggested that Vreo atrcapllus had a very restrcted det. Ths does not appear to be the case. Most of the tems found have been found n the stomachs of other vreos by Chapn (192^). Exceptons are the centpede, the tettgond, and the fulgord. Despte the consderable varety n the contents of these stomachs, there s a great deal of smlarty n the food of specmens collected n the same localtes. What the speces eats s no doubt nfluenced by the localty, the season, and the tme of day. The stomach contents of an mmature male and an mmature female taken at the same localty on two subsequent mornngs were very smlar. t appears, as s true of other vreos, that the black-capped vreo eats some vegetable matter n the fall and wnter. Over ^0% of the bulk of the stomach contents of two mmature brds taken n Mexco n December was seeds. The weather was cool and these brds may have resorted to vegetable food n the absence of numbers of nsects. An adult taken n a warmer localty a few days earler had only two small seeds n ts stomach. No vegetable matter was found n the stomachs of the specmens taken n summer. t s nterestng fnd any sand or gravel. to note that n no stomach dd t s true that the bulk of the

88 75 food s soft n nat u r e, and jztse "Tt qtfte ] thoroughly before eatng t. The stomach s farly muscularj : and the hard {sclerotzed) parts of nsects may serve as ^grndng materal. My captve brd regularly cast up pellets composed of undgested hard parts of nsects. Herrck (1 9 O) mentons that vreos are known to regurgtate such pellets. The black-capped vreo can lve wthout havng surface water avalable. hgh water content. when t occurs. Much of ts food (nsect larvae) has a The brd takes advantage of dew and ran

89 CHAPTER V ECTOPARASTES ARD DSEASE The black-capped vreo appears to be unusually free of ectoparastes. have never found a brd or a nest that had mtes, mallophaga, or.parastc dptera. Ths statement s the more vald n vew of the fact that wthn the study area other brds and ther nests had parastes of varous jsorts. One adult male black-capped vreo dsappeared from hs breedng terrtory. Ths was the only adult brd under observaton that may have ded durng the breedng season n the course of ths study. Two nestlngs ded of unknown cause(s) n 19^^. Some brds had foot trouble as a result of my placng the color bands below the metal bands (done to make the brds ndvdually recognzable n the feld). One male had a wsp of plant fber or spder web tghtly bound about hs ankle whch was swollen as a result. 76

90 CHAPTER V TAXONOMY n the course of ths study examned and measured l7^ specmens of Vreo atrcapllus from varous collectons n the Unted States (see Appendx ). found no geography cal varaton n coloraton. Northern specmens tended to be slghtly larger than southern (see Table X). Arbtrarly dvded the specmens representng breedng brds nto north, central, and southern groups accordng to poltcal boundares. Ths was a reasonable procedure because all Oklahoma populatons are farly well separated from those of Texas, and snce most of the Texas specmens came from Kerr- vlle, the Texas group was separated from the Mexcan. was not possble to compare specmens of females n a lke t jmanner because of nsuffcency of materal. There s nsuf- fcent geographcal varaton to warrant the namng of races n comparng sze n dfferent age categores (see jtable X), fnd that the oldest males tend to be the largest brds n a populaton whle the young (one year old or! j jless) females tend to be the smallest. Young males (one yeaj 77

91 78 TABLE X GEOGRAPHC VARATON N MEASUREMENTS OF ADULT* MALES Wng (n mllmeters) 1 Humber measured Geographc group Extremes Mean S.E. (mean) S.D. : Oklahoma Texas Mexco ^ Tal (n mllmeters)! Number measured Geographc group Extremes Mean S.E. (mean) S.D Oklahoma Texas Mexco S S Culmen (n mllmeters) (from posteror edge of nostrl to tp) 1 : ! 1 Number 'measured Geographc group Extremes Mean S.E. (mean) S.D ; 1 Oklahoma Texas Mexco Tarsus (n mllmeters) Number measured Geographc group Extremes Mean S.E. (mean) S.D. Oklahoma Texas Mexco * Breedng brds two or more years old.

92 79 - ' VARATON N MEASUREMENTS OP DFFERENT AGE GROUPS Wng (n mllmeters) 1 1 Number Sex Age n Extremes Mean S.E. s. d J measured years (mean) ^ 85 c T two plus ( f one or less /j 7 9 two plus one or less all ages Tal (n mllmeters) Number Sex Age n Extremes Me an S.E. S. d J measured years (mean) 85 c T two plus c T one or less 40-4^, two plus ko one or less 4-fo, all ages Culmen (n mllmeters) (from posteror edge of nostrl to tp) Number Sex Age n Extremes Mean S.E. S.D, measured years (mean) 83 ( f two plus c T one or less 'two plus one or less all ages Tarsus (n mllmeters) Number Sex Age n Extreme s Mean S.E. S. d J measured years (mean) 67 c two plus ( f one or less two plus jl 9 one or less " ^ - all a g e s. 17-2y 8_.u6a_ ^.74

93 80 old or less) are lkely to l)e larger t&an Tealds of any age,j and older females tend to be larger than younger ones. Rdgway's (190^) descrpton of the "adult" s actu-! ally of the adult male. Hs descrpton of the "young" s of! the frst wnter plumage. He fals to dstngush between the sexes, probably because he had few, f any, female spec-, ; mens at hand when he prepared hs descrpton. Characters of Plumage Useful n Determnng the Sex and Age of Specmens Early llustratons showed no dfference between the j sexes, most of these drawngs beng patterned after that by! Werner n the Bulletn of the Nuttall Ornthologcal Club ;(Coues, 1879) «A number of thngs about ths pantng suggest that the artst was ether not closely observant or was j workng from poorly prepared specmens. The colors of the jrdes and tars are wrong. There s no nterrupton of the spectacle. The nest appears to be moss and lchen covered, whch would be exceptonal were t so. No menton s made of lt by ether Werner or Brewster (1879) The only really adequate llustraton of the brd, as far as am aware, s one by L. A. Puertes (Cooke, ). Bunker (9 O) publshed a 1 photo whch shows, n black-and-whte, the dfference n pat-1 ; tern between the sexes dorsally. The head of the adult male s black except for the bold whte spectacle, chn, and throat. n fresh plumage, the nape feathers may have gray tps. Darkness of the head

94 81 vares wth age, as Bunker (9 O) suspected. Heads of males one year old (age determned by examnaton of ther prmary coverts and flght feathers) usually are gray rather than black from the posteror edge of the eye backward over the occput and nape; the blackness of the cheeks contrasts wth the gray of the back of the head; and, f the plumage s fresh, the crown feathers are notceably edged wth gray. Males n frst wnter plumage are lght gray on the forehead and crown. n females, darkness of the head apparently vares ndvdually. Brds n frst wnter plumage have lght gray on the forehead, crown, occput, and nape. The spectacle nterrupton s dark gray, contrastng wth the lght gray of the crown. n older females the forehead and area about the spectacle may be dark gray, though have seen a female whch knew to be at least three years old that had a lght gray head. The chn, throat, breast, and belly of all males, regardless of age, are whte. Those of females are washed wth buff the younger the ndvdual the stronger the buff. Adult males are strongly yellow on the sdes and flanks; n frst year brds the yellow of these areas s washed wth gray. n the 17b specmens have handled males and females are readly dstngushable by careful examnaton; only a few would cause dffculty n the feld. Some females are dark enough on the forehead and cheek to look lke males n

95 82 faded frst breedng plumage.! Two specmens, a female from Guerrero (MVZ )» and a male (?) from Morelos ( M N H O9 8 3 )» are somewhat atypcal. n most respects these specmens are lke Vreo atrcapllus, but they dffer n that the crown, nape, and back all are gray. The wngbars of the male are whte nstead of yellow, and the dark parts of the head are gray nstead of black. Ths specmen resembles a female black-capped vreo more than anythng else, but s slghtly grayer on the back. 1 Both are from the southwestern edge of the black-capped vreo* s wnter range, and from the eastern slope of the Ser- ra. They may represent a new form, or may be hybrds (Vreo j atrcapllus x Vreo hutton). have ncluded them as rec- lords under ths speces, but have omtted ther measurements Descrpton of Juvenal Plumage Ths fluffy, rather lax plumage, whch has not here- tofore been descrbed, s, generally speakng, gray above anc. whte below. The back and scapulars are lead gray, of a! shade a trfle darker than that of the top of the head, back of the neck, rump, and upper tal coverts. The lores are {whte, the spectacle whte, nterrupted antero-dorsally by! gray. Below the aurculars the whte s strong enough to form a sort of streak. The flght feathers are blacksh gray, edged (especally on the secondares) wth lemon yellow.! The! tertals are broadly edged wth yellow, as are the mddle and]

96 83 greater secôrï^dary cotterts, whôsenpâte "yettôw~tïps~^tbrm two ; dstnct bars. The alulae and prmary coverts are gray, the; wng-lnlngs whte. The underparts throughout are whte, ex cept for the flanks, whch are tnged wth yellow.! n a lvng female 22 days old the mouth-lnng was pnk; the gape pale yellow; the maxlla dark graysh horn; the mandble pnk, darker at the tp; the feet blue, tnged wth pnk; the rdes dark brown. Other juvenles whch have handled were smlar. So far as have been able to as*f jcertan juvenal males do not dffer from juvenal females. The eye color changes durng the frst wnter to the reddsh brown of breedng brds. Brds wth unossfed Skulls collected n December stll had dark brown rdes. Adults taken at the same tme had red-brown eye color. Breedng brds all have the typcal eye coloraton. Ths change also occurs wthn a year n the red-eyed vreo (Dwght, ). The color of the tars changes from pnk to graysh blue shortly after the young leave the nest. have seen ong young brd whose tars were blue before t left the nest. thnk that brds whose legs change color early n ths way are males, but specmens must be collected to prove ths pont. The Molt There s no natal down. The juvenal plumage s lost

97 84 The juvemï 'pfîmry wng^ hoverts, remges, and rectrces are retaned untl the frst postnuptal molt. Other vreos that have examned, whch! 1 jnclude the warblng, Phladelpha (V. phladelphcus), : Bell's, yellow-throated (V. flavfrons), and whte-eyed show retenton of the prmary coverts so that ths appears to be a îcharacter of the genus. Dwght (1900) ndcates only that ; the remges and rectrces are retaned n the vreos n New ïork, except for the whte-eyed vreo n whch he thought : they were. found specmens of Vreo grseus n whch ths was not the case however, and so, n some nstances at least, the speces s not dfferent n ths respect from other vreos. There may be geographc varaton n the extent of the postjuvenal molt n vreos. There s a partal, early wnter (prenuptal) molt of head feathers n the male black-capped vreo. do not know jlf t occurs n the female as well. had wondered why never saw any gray-headed males (young males are gray-headed after the postjuvenal molt) n the sprng. Examnaton of November specmens showed a molt n progress on the head of males, both adult and brds of the year (aged on the bass of jskull ossfcaton). Furthermore, captured a male at the nest whch had very worn prmary coverts early n the breedng season, yet ts head was black, not gray. t was a frstyear male judgng from plumage characters. t wll be nter-j ^ bstng to learn whether such a molt occurs n any other vreo.

98 85 *_.-.. ^..^-- -g * -- - M "' m m'"'"-- p?he black-capped vreo s the only vreo showng marked sex- lual dmorphsm and ths specal molt may have arsen (or been retaned) n conjuncton wth ths character. n other words, black-headed males may be better able to obtan mates than ^ray-headed (female-lke n appearance) ones, so the molt to jnsure breedng of frst-year brds. The postnuptal molt, whch s complete, begns n jearly July n Texas, and n mddle and late July n Oklahoma; ;! t starts n the anteror parts of the body, and after t s ^ d e r w a y the molt of the prmares and secondares begns, {Proceedng from the frst to the tenth. When most of the prmares have been replaced, the rectrces are lost, usually jal at once w t h the result that n August there are many bob-taled brds. Beng wthout a tal does not appear to handcap the brds n any way. once accdentally pulled the rectrces out when catchng a female. She contnued n- jcubaton and reared a brood n her bob-taled condton. The progress of the postjuvenal molt s descrbed n the secton on development of the young (see page -5).

99 CHAPTER V DSTRBUTON The black-capped vreo s lmted n ts breedng to! : the south central Unted States and north central Mexco. t occupes an area n whch eastern floral and faunal elements meet wth western, and northern wth southern an area of hybrdzaton and ntergradaton. Furthermore, the specal labtat chosen by the brd s n tself ntergradng and transtonal and therefore very localzed wthn the area. Sght records and one specmen place the northernmost] pont of occurrence (as an accdental summer vstant) n southeastern Nebraska (Brunner, ). The speces has been known to breed as far north as central Kansas but, though Tordoff ( ) lsts two sght records n recent years, the jstatus of the speces n Kansas s uncertan. vsted localtes n whch the black-capped vreo had been found breedng and faled not only to fnd the speces, but also to! '! fnd any habtat comparable to that now occuped by the brds! n other areas. beleve that land use (overgrazng) and j clmatc condtons (drought) have made the former habtat r 8 6

100 87 souttërn ^ soüwwëst^yn TKsEn. s a 'lnad c ë p TRë^^oFElïërnrj ; j most breedng area have found s n northern Oklahoma ;(Major County), j The southernmost known breedng grounds are n central Coahula, Mexco (Serra Madera, east of Ocampo), }s also the western lmt of breedng (103 W. Long,), Ths The eastern lmt s at approxmately 97 W, Long, (Tulsa, Oklahoma, and Dallas, Texas), The speces wnters along the west coast of Mexco from the foothlls (at least as ngh as 2700 feet) of the Serra Madre Occdental to the coast (Mazatlan, elevaton 10 jfeet), from southern Sonora to Jalsco and Mchoacan, and probably farther south. and one from Campeche, There are two records from Guerrero Observatons by collectors for Dr. Robert T. Moore, by Dr. Allan R. Phllps, and by myself ndcate that southern Snaloa and Nayart are the center of the wnterng grounds. saw more brds n Nayart than n southern Snaloa as many as three n a square mle n a mornng near Las Varas, Nayart. Dr, Moore wrote me that though he had materal from about the same number of collectng statons n Nayart, Jalsco, Durango, and Snaloa, about; fve tmes as many specmens had come from Snaloa as from the other states, All records known to me are lsted n Table X, jwhch s arranged frst by state, then alphabetcally by ^omty,^^_and _ lm t ly _ ^ _ ja ^

101 88 l W ë g ë n e r â T ro'cà^^ Ond eïf" sëvëral'lïeâa'nî^ propose to dscuss the dstrbuton of the speces as know lt now. Oklahoma At the tme of ths study, the black-capped vreo was known to breed n Caddo, Dewey, and Major countes. t was 'observed n Blane and Canadan countes and t very lkely breeds n these countes. t has been seen n Beaver, Gleve^ lland, and Payne countes n summer. t may occasonally breed n the latter two, as well -as n Oklahoma county. The speces has not been reported from Greek or Tulsa pountes for over twenty years. saw what looked lke sut- jable habtat n the eroded sandstone hlls of ths regon, but dd not have tme to search the area to my satsfacton. The speces no longer breeds n Comanche and Murray 1 jcountes. Despte contnued search, no one has found the [brd recently n these countes. n both countes, the areag n whch the brd was found have been m uch dsturbed by the! presence of people. n both the Arbuckle and the Wchta Mountans there are parks and resort areas. The Wchta ares, ls further dsturbed by bombardment of guns and by mltary banuevers on the mltary base nearby. Specal effort was made to fnd the speces n Woodward, Woods, and Alfalfa countes, but none were seen there. The habtat n these countes may have been sutable at one

102 lne of the Balcones Escarpment through northern Bexar, east- prn Comal, eastern Hays, and eastern Travs countes. Sut- 89 jttme, but s" not ^ b now "because" of'"ôv8rgrbw^tb"""ana^"tb o shrubbery due to drought and overgrazng. n other words, the ravnes n northern Oklahoma are now sparsely lned wth; medum-szed oaks and cedars, but there s nsuffcent cover at heghts of two to sx feet. At present the speces appears to be lmted to leroded, red sandstone (Perman) ravnes and canyons whch support a scrubby growth of blackjack oak and post oaks and red cedar. The gypsum ravnes of northern Oklahoma and! : southern Kansas whch once supported populatons of the j! b l a c k - c a p p e d v r e o a p p a r e n t l y n o l o n g e r, h a v e s u t a b l e v e g e t a - * t o n. Texas The black-capped vreo has been found locally throughout central Texas. The center of ts dstrbuton there les n the hll country and Balcones Escarpment, an oak-cedar covered margnal porton of the Edwards Plateau. As far as have been able to determne, the brd now breeds no farther west than Devl s Rver n northwestern yalverde County and no farther south than central Uvalde County. n the southeast, the breedng range follows the able habtat becomes sparse and spottly dstrbuted north ol the San Saba and Colorado Rvers. n fact, the only recent j

103 Drd and for habtat that mght attract t n the Davs, ]hso8, and Glass mountans, and n Terrell, Crockett, western Valverde (Pecos Rver Gorge), Reagan, western ron, ^chlecher, Sutton, western Kmble, and San Angelo countes. found remnants of the habtat n all these places, suggestj 90 records n nor the rh Texas "are' and j northeastern Slls countes. 1 : To check reports of the speces from eastern Texas n : jthe "Bg Thcket" area, vsted the eastern edge of ths! 1 area whch les between the Trnty and Sabne Rvers south j '! of Nacogdoches. dd not see any vegetaton that was any- j! thng lke that whch the brd now occupes n other areas. : Untl specmens are taken n ths regon, regard such re- ports as dubous, have corresponded wth several observers from Houston and none have ever seen the brd n the area, although Selle (1933, 1934) lsts t n hs books coverng the Houston area (ncludng the Bg Thcket). The speces appears to have suffered severe reducton n numbers n the Trans-Pecos country and along the western sdge of the Edwards Plateau. made careful searches for the jng that n prevous years they were sutable. Now the vege- taton s almost gone because of drought. For years the gorge near the mouth of the Pecos Rver has been occuped by black-capped vreos, but could fnd hone there n 1955 and 195^» A flood scoured the vegetaton j jfrom the lower porton of the canyon n and drought ha^ j

104 91 klled most o f ü#ër slopesv ^ T M s shrubbery appeared to have been sutable habtat n earler j years, but n 195^ and 19^6 stood dead and bare. n Lgon Canyon n Terrell County the same condtons prevaled. n the Ghsos Mountans, half or more of the trees and shrubs lvng at the * ft. level, n » were dead n The hllsdes between Juncton and Ozona had nnumerable dead pedars and some dead oaks on them, all apparently klled by the drought. Near Weatherford, Parker County, and through Palo Pnto and Stephens countes to Breckenrdge there s some jhlly terran covered wth cedar-oak growth that mght offer sutable habtat. Ths sort of habtat also extends nto southeastern Graham and southern Jack countes. dd not fnd any black-capped vreos at Possum Kngdom Lake. dd not check elsewhere n ths area. n general the shrub 'growth appeared to be a lttle too thn to provde habtat jfor the speces, but there well may be localzed areas that are sutable. A set of eggs allegedly collected n Cameron County, Texas, may or may not have been taken there. Bard (Syj.) lsts Woodhouse's type as from El Paso obvously an error! (see page 1). There s no other record of the brd from El Paso.

105 Mexco The frst breedng record for Mexco s one by Renardo (8 8 6 ) who wrote only that he found t breedng n the Ro Grande Valley. Specmens taken n May by Unversty of Kansas collectors n central Coahula ndcated that t was breedng there. Other specmens taken n Aprl land August suggested breedng, but snce the speces does not! ' reach ts northern breedng grounds untl md-aprl or later;! land fnshes breedng n the southern part of ts range n! July, these specmens mght, t seemed, represent mgrant or wanderng brds. To make certan of the stuaton, and also jto study the habtat of the southern part of the breedng jrange, spent June, 195^» n central Coahula. Breedng populatons were found n two small mountan chans (Serra Padlla and Serra Madera) about Ocampo, Coahula. Fve jnests were found. Specmens taken n the Serra del Carmen (Mller, 11955) and the Serra del Pno (Van Hoose, 1955), whch le to the north of Ocampo, probably represent breedng populatons, ÿhe Serra del Pno extends nto Chhuahua, so the speces may breed n the eastern part of that state. was not able jto check the Serra de los Alamtos or the Serra de la Palma, both of whch are a lttle south of the area n whch found, the brds. attempted to fnd the speces n the mountans about Saltllo, stll farther south. Here at 6500 feet, but not at lower elevatons, there was some oak chaparral, but

106 93 ad not fnd the vï^b8. " too cool at nght for the speces. n reachng the mountans south and southwest of Hdalgo del Parral, went frst to San Francsco, then soutl jn northwestern Durango through Rancho Blanco and Bojto (not; on any maps n my possesson ncludng a U.S. Ar Force aeronautcal chart wth a 1:1,000,000 scale) to the head of the Ro Verde (at the Contnental Dvde) and as far up nto the mountans as a place called Las Flores, whch les between 90OO and 10,000 feet elevaton and at whch there are m a g nfcent growths of pne. partcularly searched oak chaparral covered slopes lyng just below the level of plnyon [pne (about ^^00 feet). chose ths area because t les [drectly between the breedng grounds and the wnterng jgrounds, and at the head of some of the rvers that lead to large barrancas through whch black-capped vreos ma y be jchanneled n mgraton (Moore, 1938). t appears that the j speces must pass through ths regon, and f sutable habtat exsts, t may stay to breed. However, dd not fnd t. The chaparral of the lower, warmer slopes had been largely destroyed by overgrazng and drought. That whch mght have been adequate on the upper slopes was probably at elevatons too hgh for ths speces. Certan solated areas may be sutable, but snce few roads are passable n ths re4 j gon these areas ma y well reman undscovered for some tme.!! The record from Santa Le onor. Tamaulpas (Phllps,!

107 9k 1911 )" süggèsts vtréô ; eastern slopes of.serra Madre Orental west of Cudad Vctora, but to date no one has dscovered t there. have passed through Cudad Vctora a number of tmes and have thought that the shrubby growth along the hghway south of ths cty resembled that of the wnterng grounds more than that of the breedng grounds. Ths record (f vald) may smply be one of accdental occurrence, a mgrant that wandered astray. : : Non-breedng brds have been found n Mexco between j August 27 and March 20, and possbly can be found n Aprl. Scattered localty records n September and March probably represent mgrants, the rest, wnterng brds. Moore (9 3 8 ) has suggested that the black-capped vreo follows the Mexcar. plateau to the heads of rver gorges leadng westward to the coast, thus enablng t to by-pass the hgher alttudes of the Serra Madre Occdental. Ths well may be the case snce jths route s the shortest between the wnterng and breedng 'grounds and t offers a way through at least some habtat not unlke that n whch the brd wnters and breeds. However, scattered records also ndcate that t s jpossble for the brd to pass over the mountans. jtaken at 9>00 feet elevaton on Volcan de Toluca. One was, myself, jtook a captve to elevatons between 9500 and 10,000 feet n the Colorado Rockes n late August, and found that the brd (ld not suffer f fed and kept warm at nght. t seems that

108 95 a'fattëheaergrm t-^prâctnr^ÿlerâ\^-m ^^ jto pass over the Serra Madre Occdental.

109 TÆBXîE - -. DSTRBUTONAL RECORDS OP VREO ATRGAPLLÜS (See Appendx for abbrevatons of names of museums) Nebraska: Localty Douglas County Date Observer Reference Remarks Omaha 6/19/1894. S. Trostler Brunner, 896 One seen, Sarpy County 1 Bellevue L. Skow Brunner, 896 Meadow ^/ 19/1921 A. M. Brookng and J. E. Wallace Specmen at HM. Kansas : Localty Date Observer Reference Remarks Comanche County Ne^ar Rumsey Sect. 13, t34s, r6w V? / l 88^ N. 8. Goss Goss, 1385 Two specmens at Bunker, 9O KSHS; one at KÜ. Douthtt, 1919 Nest found ^//85.

110 TABLE X Contnued Kansas Contnued pocalty Date Observer Reference Remarks powley County Wnfeld 1902 L. T. Weeks Psh & Wldlfe Servce Records Common summer resdent. Wnfeld {./22/l909 Cooke, 1909 Lsts record. Donphan County Bandena $ /9 /9 l7 p. B. Zmmerman U.S. Psh & Wldlfe Servce Records vo ->) Gray County! Cmarron 9/2-10/1916 W. P. Woods U.S. Psh & Wldlfe Servce Records larvey County Halstead 5/16/1951 E. Ruth Tordoff, 1956 Sght record. îodgeman County ct. 3^» Set of eggs at BU

111 TABLE X Contnued Kans as C ont nue d Localty Rley County Date Observer Reference Remarks 1 Manhattan 6/18/1953 S. Searles Oklahoma: Tordoff, 1956 Sght record. Localty Date Observer Reference Remarks Beaver County Gate 5/5/1923 W. E. Lews Nce, 1931 Sght record. vo 00 Blane County C. D. Bunker Bunker, 1910 Several specmens collected; a number of nests found. Blane County 6/27/1934 M. Leonard Specmen at KU, 8 m. N.W. of Watonea 6/3/19SS G. M. Sutton R. R. & J. Graber Several seen.

112 TABLE X Contnued Localty Caddo County 0 kl ahoma G on t nu e d Date Observer Reference Remarks 3 m. S.W. of Cogar l/26/1953 G. M. Sutton Specmen at OU. 3 m. S.W. of Cogar l(./2^/l9^. R. R. & J. Graber to 9/17/19^4 G. M. Sutton Pour specmens taken. A number of nests found. 3 m. S.W. of j./l7/l955 R. R. & J. Graber Cogar to 8/3/1955 A number of nests found. Set of ^ eggs at OU. '-c 3 m. S.W. of Cogar Canadan County [. m. S.E. of Hnton, Devl's Canyon,,,,.956 R. R. & J. Graber to 6/5/9$6. 7/22-29/1956, and 8/2/1956 5/3/1953 R. R. Graber D. P. Parmelee Fourteen nests of 12 pars found. Specmens taken; 1 skn, 2 skeletons, 2 alcoholcs. Par seen.

113 TABLE X Contnued Oklahoma Contnued Localty Date Observer Reference Remarks Cleveland County Norman 1^ m. E. of Norman 5/11/1926 6/2/l9S$ M. M. Nce G. M. Sutton J. C» Johnson, Jr. Nce, 1931 Sght record. Sght record. 15 m. E. of Norman Comanche County 6/5/1955 J. Graber and 6/15/1955 Sngle male on terrtory, had bult rm of nest! o Lower Narrows of 6/).-5/ l929 W. Cache Creek n Wchta Mts. M. M. Nce Nce, 1929 A sngng male seen. Cache 6 / 1 9 / T. D. Burlegh Specmens at USNM ]reek County Sapulpa 7/20/1929 T. R. Beard Nce, 1931 Two nests, evdence. No

114 j TABLE X Contnued O k l a h o m a - -C ont nue d pocallty Date Observer Reference Remarks be w e y C o unty 12 ml. S.E. of Sellng ^/13/19^^ G. M. Sutton Par collected. 12 ml. S.E. of! Sellng $/2^/l9^$ G. M. Sutton Found nest n e w l y bult. 12 ml. S.E. of Sellng 6/3/19$^ J. Graber B anded par. 12 ml. S.E. of Sellng 8/2/ 19^^ R. R. and J. Graber Sav/ male agan. o Major C o u n t y 6 mles E. of Chester 7/ 12/1955 R. R. and J. Graber P o u n d nest, b a n d e d par. 8/ 2/1955 R. R. and J. Graber Banded one juv. from ths nest. Murray County Arbuckle Mts. 6/17/1920 M. M. Nce Nce, 1931 Sght record. Arbuckle Mts. 2^/23/1927 M. M. Nce Nce, 1931 Found nest w t h tny chcks.

115 TABLE X -Contnued Oklahoma Contnued [Localty [Murray County Date Observer Reference Remarks ' Arbuckle Mts 1j./26-27/1937 G. M. Sutton K. W. Haller Several specmens!, Sutton made photp of nest (unpub- lshed). Oklahoma County Spencer 5/2/1938 J. W. Harmon and 5/9/1938 Psh and Wld Lfe Servce records Par buldng nest. o ro Payne County Lake Carl Black- 5/20/1942 well P. M. Baumgartner Baumgartner, 1944 Male sngng, not seen thereafter. Tulsa County Near Tulsa G. W. Morse Morse, 1927 Nce, 1931 Pound three nestsl Eggshells and! nest at M V Z. Near Tulsa 5/12/? H. A. Yocum Yocum, 1935 Nestng Tulsa 5/20 to 7/20 E. R. Force (1930) Force and Hughes, 1940

116 TABLE X -Contnuad Taxas : Localty Date Observer Reference Remarks Bandera County 3/19/1884 G. H. Ragsdale Cooke, 1888 have not located ths specmen. Bastrop County Slum (Alum) Creek about m. J.W. of Smthvlle J. A. Sngley Sngley, 887 Found nest. Brewster County Glass Mts. 15 mles N.E. of Marathon Aprl 1933 G. M. Sutton Van Tyne and Sutton, /2^/1935 G. M. Sutton Van Tyne and Sutton, 1937 Specmens at CM. Chsos Mts. Blue Creek 1^/30/1936 T. P. Smth Oberholser Sght record, Par seen. Chsos Mts. Lost Mne Tral 4/30/1949 A. D. Cruckshank Cruckshank Sght record. One seen.

117 TABLE X Contnued Texas G ont nue d Localty Date Observer Reference Remarks Bexar County San Antono 3/31/1890 Specmen at USNM. Balcones Escarp, 23 m. W. of San Antono 1^/2S/1889 Specmen at USNM. 18 m, W. of San Antono 6/ 8/1890 H. P. Attwater Specmen at AMNR. San Antono S/4/1898 P. W. Smth, Jr. Fsh & Wldlfe Servce records Nestng, 3 eggs. O West and N.W. of San Antono H. P. Attwater Attwater Reported nestng. A. J. Krn and R. W. Qulln, 1927 N.W. of Classen 6/20/1936 on W. Pork of Cbolo Creek R. W. qulln Psh and Wld- Nest wth 3 eggs lfe Servce reported, records

118 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Burnett County San Gabrel Rdge 1898 V. Baley Oberholser Observer heard several. Callahan County Putnam ^y/1926 A. J. Krn Psh & Wldlfe Servce records Sght record. Cameron County Brownsvlle May 1892 P. B. Armstrong Specmen n Catalogue PAC Set of eggs at USNM. o VA Comal County 23 m. N.E. of New Braunfels 5/6/1878 W. H. Werner Coues, 1879 Specmen at USNM, 5/1^/1880 6/12/1881 S/20/188^. E. P. Predley E. P. Predley G. B. Benners Egg set at AMNH. Egg set at AMNH. Benners, Set of eggs at 1887 USNM.

119 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Corna County 5/17/1885 E. P. Predley Set of AMNH. s at Aprl, 1838 T. S. Glln Several (6 ) specmens and a nest at PMZ. 5/29/1888 G. B. Benners Set of eggs at G8NM. El Rancho Cma 5 m. W. of Wmberley 3/2/l956 5A - 2S/19^ / / J. Graber Sght record. Pound 18 nests. No specmens. Photos made. Comanche County 50 m. N.E. of Gamp Verde 5/2/1878 G. H. Ragsdale Deane, 879 Ths specmen used to be at PM. Has dsappeared. H. Nehrlng Reported breedng. Concho County W. Lloyd, 1867

120 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Cooke County Red Rver near Warren's Bend 6/16-17/1880 G. H. Ragsdale Ragsdale Young just out of nest. 6/25/1880 G. H. Ragsdale Specmen used to be at PM. Has dsappeared. 5/29/1888 G. H. Ragsdale Specmen at UMMZ. Ganesvlle +/17/885 (Ragsdale) Cooke, 1888 o -o Ganesvlle Specmen at CMHH. Dallas County Southwestern part of county 1930 to 1956 J. E. Stllwell Stllwell, 1939 Lsts as summer resdent. l^/l to 9/5 C. Kelley Kelley, 1935 Lsts as uncommon nestng. Boy Scout Gamp west of Duncanvlle and Campfre Grls' Camp near Cedar Hll. May to July C. T. Gll ^6 Sght records.

121 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Dallas County Near Cedar Hll 5/11/1938 Mrs. T. E. Wnford Saw young brds just out of nest. Mountan Greek '-// M r s. Wnford and Mrs. Kennedy England Sght records. m. S.W. of Dallas 2^ m. N. of Cedar Hll Near Duncanvlle 5/21-22/1956 J. E. Stllwell Sght records. 8/7/19^6 E. C. Frtz Sght record. 8/11/1956 Geth Osborne Sght record. M O CO Near Duncanvlle 9/3/19^6 E. C. Frtz and G. Osborne Sght record. Eastland County Csco 1^/29/1926 A. J. K r n Fsh & Wld- Par seen. lre Servce records

122 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Edwards County 7 m. S. of Rock Sprngs 7/14/1902 M. Cary Specmen at USNM, 9 m. N.E. of Rock Sprngs ^6 E. B. Kncad, Jr. Sght records. Ells County Near Mdlothan Erath County May to July C. T. Bll 1937 to 1946 Sght records. O so Northeastern part of Co. 5/3/1878 G. H. Ragsdale Deane, 1879 have not located any specmen. Fayette County H. Nehrlng Nehrlng, 1396 Sght record Gllespe County Fredercksburg (Baron Sprngs) 9/11/1894 F. Grasso Fsh and Wldlfe Servce records

123 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Hays County El Rancho Cma, Boy Scouts of Amerca Houston Counc l Area 6/23/1955 Carl Aken Saw several, El Rancho Cma, Boy Scouts of Amerca Houston Councl Area 5A - 25/9^6 6/7/1956 7/2-10/1956 R. R. & J. Graber Several nests found. 2 m. S. of Wmberley 3/25/1956 Aprl, May, and July, 1956 J. Graber Several seen; specmen taken 7/9/56. o 2 m. E. of Wmberley, Thornton Ranch 3/26/1956 Aprl, May, and July, 1956 J. Graber Several nests found. At least sx resdent males Kendall County Boerne 3/27/1880 N. C. Br own Brown, 1882 Specmen at PU. Boerne 5/20/1892 F. M. Woodruff Fsh Sc Wldlfe Servce records. Specmen at GAS.

124 TABLE X Contnued Texas -C ont nue d Localty Date Observer Reference Remarks Kerr County Turtle Creek 6 /3 / H. Lacey Lacey, 19 Egg set at USNM. Kerrvlle ^/ 7/l899 V. Baley Egg set at USNM also specmen. Turtle Creek Japonca Kerrvlle Kerrvlle Lacey's Ranch near Kerrvlle ngram Kerrvlle 5/5-7/1900 H. P. Attwater 1902 V. Baley 1907 A. P. Smth 1910 J. E. Thayer 1910 A. P. Smth 1910 P. B. Armstrong Egg set at USNM also specmen at DvnH. Specmens ; see Appendx for lst of specmens. Specmen at BU. Specmens. Specmen at GAS Kerrvlle ^/6/95 P. B. Armstrong Egg set at YPM, also specmens. ngram 1915 A. P. Smth Specmens.

125 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Kerr County Kerrvlle 1917 H. Lacey Fsh and Wldlfe Servce records Kerrvlle 8 m. 8. W. of Kerrvlle 6/10/1932 T. Smth 1937 B. E. Ludeman Fsh and Wld- Nestng record. lfe Servce records Specmens, see Appendx. ro 20 m. W. of Mountan Home 1937 D. W. Lay Specmen. 12 m. S.W. of Kerrvlle 1940 A. C. Twomey Specmens Kerrvlle L. R. Wolfe Sght records. Kerrvlle 8/28/1955 R. R. and J. Graber Saw two males and one female. Kmble County Juhcton 5/6/1939 T. D. Burlegh Specmen at USNM.

126 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Knney County 25 m. N. of Brackettvlle, Ted P. Dunham Ranch Lee County 7/13/1956 R. R. Graber Specmen, Kehrlng Nehrlng, 896 Llano County Rdge overlook- 7/16/1956 R. R. & J. Graber ng nks Lake Mason County Sght record. t-* B. Henry Oberholser Reported rare, breeds. McLennan County Near Crawford on Bluff Creek C. D. Oldrght J. K. Strecker Strecker, 1927 Strecker saw only 6 durng 35 years* Bosque Hlls near Waco 6/3/1935 T. P. Smth and 6/13/1935 Specmens at YPM, Waco Set of eggs at BU,

127 TABLE X Contnued Texas- C ontnue d Localty Date Observer Reference Remarks Medna County Camp Verde 4/20/1878 Norrs Deane, l8?9 The present Camp Verde s n Kerr County. Dverson Lake [1./3/1926 A. J. Krn Fsh and Wld- Par seen. lfe Servce records 18 ml. N. of Castrovlle 5/27/1927 A» J. Krn Psh and Wld- Nestng; several lfe Servce nests found, records 18 ml. N. of Castrovllle 6/21^/1930 A. J. Krn Ro Medna 6/25/1931 H. W. Brandt Fsh and Wld- have not lollfe Servce cated ths speclrecords men. Dverson Lake 6/9/ ml. N.W. of 5/26/1934. Ro Medna Ney Cave, 20 ml. 5/9/1953 N\ of Hondo ^ ' --- A. J. Krn A. J. Krn E. B. Kncad, Jr, Fsh and Wld- Nestng. lfe Servce records Specmen at UMvZ. Nest found. Fve seen.

128 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Menard County San Saba Rver near Menard 5/7/1918 A. P. Smth Smth, 1918 have not located any sped* men. Reagan County Near head of Concho Rver 1883^1886 W. L. Lloyd Oberholser Reported breedng. Real County Prade Ranch 1933 R. W. Qulln Oberholser Sght record. Tarrant County 1915 R. Graham Graham, 1915 Lsts as breedng, but omts from subsequent lsts. Fort Worth 6/27/1916 Psh and Wldlfe servce records One par reported nestng. Fort Worth May 1937 M r s. Wade Smth (W. M. Pulch Sght record.

129 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Terrell County 13 m. S. of Sheffeld, Lgon Canyon 6/l^/l9j-9 W. A. Thornton Thornton, 1951 Specmen at TJ. Tom Green County San Angelo 9/6/1884 9/16/1885 Cooke, /26/1886 9/1/1886 W. Lloyd Lloyd, 1887 Specmens at (JSNt/L Nestng reported. t-* ^ Travs County Aus t n 4/22/1689 C. D. Oldrght Specmen at A V M H. Austn 4/16-17/1893 Fsh & Wldlfe Servce records Along Barton Creek at Marshall Dam 1941 Mrs. Love Whtaker Sght records. 15 m. N.W. of Austn 194^-194& R» Bedcheck Reported nest. On W. sde of Austn E. B. Kncad, Jr. Sght records.

130 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Travs County Near Austn 7/17/1956 P. S. Webster R. R. & J. Graber Saw two males. Taylors Slough near Lake Austn 9/l?/l956 F. S. Webster Saw one. Uvalde County Near Sabnal 5/1/1953 E. B. Kncad, Jr. Sght record. 18 m. S. of Leakey, Menada Ranch R. R. & J. Graber Saw several. Specmen taken. Valverde County San Pedro Rver May l85l Woodhouse Stgreaves Report, 1854 Specmen at AMNH, San Pedro Rver (June) '1850' J. R. Clark Cassn, 1862 Specmen at ÜSNM, Ro San Pedro 5/6/878 Devl s Rver Pecos Rver 7/22-23/1902 M. Cary 8/1./1902 M. Cary Specmens at USNM.

131 TABLE X Contnued Texas Contnued Localty Date Observer Reference Remarks Valverde County Langtry 4/26/1901 H. C. Oberholser S p e c m e n at USNM, Mouth pf Pecos Rver Mouth of Pecos Rver 5/22/1900 V. Baley Baley, 902 Specmen at U S N v î. Nestng. 8/27-28/1890 W. Lloyd Specmens at USNM, Comstock 4/23/1901 L. A. Fuertes Specmen at CU, Mouth of Pecos Rver 5/24/1938 G. H. Lowery, Jr. Specmen at LSU, M GO Campeche, MEXCO Localty Date Observer Reference Remarks 1880's J. Renardo Renardo, 886 Seen n wnter.

132 TABLE X Contnued Coahula, Mexco Localty Date Observer Reference Remarks Sabnas 4/19/1910 H. H. Kmball Specmen at MVZ. Serra del Pno, elev ft.; 6 m. W. of Acebuches 7/3/9S2 S. Anderson Van Hoose, 195S Specmens at KU. Serra del Carmen, elev. 4/23 27/l9^3 A. H. Mller 2000 ft.; 2 ml. W. of Pedra Blanca Serra Padlla, 16 m. 2/8-9/19S4 R«W. Dckerman E., 18 m. N. of Ocampo Serra Padlla, 16 m. E., 18 m. N. of Ocampo 6/l3-l4/l9S6 R* R. Graber, J. Graber, and H. C. Land Serra Madera, 32 m. by 6/17-18/19^6 R. R. Graber, road westward from Ocampo, J. Graber, and Goah., through. LaPasa, H. C. Land San Pedro, Buenos Ares "and LaCruz Mller, 1922 Van Hoose, 1922 Specmens at MVZ. Specmens at ^ EU. Two nests found. One held 4 young about 6 days old. Three nests found. Two wth eggs, one just c ompleted.

133 TABLE X Contnued Durango, Mexco Localty Date Observer Reference Remarks Rancho Guasmal, on lat, 2^ 6 m. W. of Brmoa whch les northwest of ramazula 10/21/ /13/1937 C. C. Lamb Specmens n M C :OC, Three klometers (1.3 mle) N.E. of Tamazula 11/21/ /10/1937 C. 0. Lamb Specmens n MG :00. Guerrero, Mexco ro o Localty Date Observer Reference Remarks Rncon 1888 Mrs. H. Smth Specmen n BM. hlpancngo S/S/g+O W. W. Brown Specmen at MVZ.

134 TABLE X- Contnued Jalsco, Mexco Localty Date Observer Reference Remarks Guadalajara, Barranca de Portllo 1/12/1891 A. C. Butler Specmen AMNH. at Sapotllo, 22 m. 3.W. of Autlan 2/19/1952 2/21/1952 C. C. Lamb Specmens n MC :O C. San Sebastan (whch Les south of Tepc, Nayart) 3/19/1955 A. R. Phllps Sght record. Mexco, Mexco h-> ro Localty Date Observer Reference Remarks North slope of Volcan de Toluca near jfexco Cty, elev ft. 9/11/1893 E. W. Nelson Psh & Wldlfe Servce records Specmen USNM. at Mchoacan, Mexco localty Date Observer Reference Remarks t en mles N.W» of Tqucheo (whch les sr.w«of Hue tamo) 1/1/19^3 C. C. Lamb Specmen n M C :OC.

135 TABLE X Contnued Morelos, Mexco Localty Date Observer Reference Remarks South slope of Cerro Cuautepetl (north of Cuernavaca, west of îutxlac) D. W. W a r n e r Specmen at! MMMH. Nayart, Mexco Localty Date Observer Reference Remarks Three and a half m, 3.W. of Tepc 8/27/1938 C, C, Lamb Specmen M C :OC, n ro ro ]hacala (whch les south of San Bas, vest of Las Varas) 3/15/1941 C, C, Lamb Specmen MC :OC. n San Bas 3/19/1948 C, c. Lamb Specmen M C :O C. n Dne m. W., 6 m. 8. of Compostela 11/30/1952 A, R, Phllps Specmen MT, at 'Jear Las Varas (whch les west of Compostela) 11/ / A R, Phllps Specmens MT. at fourteen and a half m, #, of Tepc, elev. f700 ft. 10/8/1955 A, R, Phllps Specmen MT, at

136 T A m r x T l ~ Côn't nüe a~ (Ocalty ÎÎ.N.E. of Santa Mara del Ore {whch les of Tepc) Nayart, Mexco Contnued Date Observer Reference 10/10/1955 A. R. Phllps Remarks Sght record. Las Varas 12/28-29/ R. R. and J. Graber Specmens at OU. Snaloa, Mexco Localty Date Observer Reference Remarks Mazatlan Aprl 860 s A. J. Grayson Specmen at USNM. \) Rosaro 12/18/1933 l/6/]^93l 2/26/1935 C. C. Lamb Specmens n MG :00, Lhele (S.W. of Concorda, W. of Vlla Jnon) 3an gnaco (N. of "Vlazatlan about halfway to Culacan) 2/9/1935^ 2/15/1935 3/18/1937 3/20/1937 C. C. Lamb Specmens n MG :OG. G. C. Lamb Specmens n MG :O C. guana 2/21/ G. Lamb Specmen n MG :OG.

137 TABLE X Contnued Snaloa, Mexco- Contnued Localty Date Observer Reference Remarks Copala (N.E. of Concorda) elev ft. Concorda (3 m. W.) 1/13/1947 K. E. Stager 1/25/ /21/1955 R. R. and J. Graber Specmens at L A C M. Specmen at OU. Sonora, Mexco Localty Date Observer Reference Remar ks Cudad Obregon Nov A. R. Phllps rv) Sght record, f- San Lus Potos, Mexco Localty Date Observer Reference Remarks Twenty mles south of Valles Easter 1947 «R. Davs Sght record Tamaulpas, Mexco localty Date Observer Reference Remarks Santa Le onor (11 m. of Cudad Vctora) 4/12/1908 P. B. Armstrong Phllps, 1911 have not located ths specmen.

138 TABLE X Contnued Mexc o Localty Date Observer Reference Remarks Ro Grande Valley 1880's J. Renardo Renardo, 1886 Reported nestng. M r o VA

139 MAP DSTRBUTON OF VREO ATRCAPLLUS RECORDS N NEBRASKA Symbols : o sght record Specmen

140 MAP DSTRBUTON OF VREO ATRCAPLLUS RECORDS N KANSAS r o C o w l 6 ^ Symbols : o Sght record» Specmen Eggs, nest, or juvenle specmens Westng reported

141 MAP V DSTRBUTON OP VREO ATRCAPLLUS RECORDS N OKLAHOMA Canadan rv) 00 Symbols O Sght record Specmen Nest, eggs or juvenle specmens Nestng reported

142 MAP V DSTRBUTON OF VREO ATRCAPLLUS RECORDS N TEXAS 30 Countes : M ro SÛ 1. Bandera 2. Bastrop 3. Bexar fj.. Brewster 5» Burnett 6. Callahan 7. Cameron 8. C omal 9» Comanche 10. Concho 11. Cooke 12. Dallas 13. Eastland 14. Edwards 15. Ells Erath Payette Glle spe Hays Kendall Kerr Kmble Knney Lee LLano Mas on McLennan 28. Medna 29. Menard 30. Reagan 31. Real 32. Tarrant 33. Terrell 3+. Tom Green 3^. Travs 36. Uvalde 37 «Symbols : o Sght record Specmen Eggs, nests, or juvenle specmens Nestng reported

143 SoMORA MAP V DSTRBUTON OF VREO ATRCAPLLUS RECORDS N MEXCO S\mavoa * D U M A N O O V.\ns POTOSl U) O Guuf o( HCKlCO Symbols : o Sght record Specmen Eggs, nests, or juvenle specmens Nestng reported M ï c a o a c a» AMTBCM PA«lP\C OCAAM buatepala

144 j CHAPTER X OTHER VERTEBRATES N AREA OCCUPED BY BLACK-CAPPED VREO AN D TS RELATON TO THEM n Oklahoma, the snakes saw n the area occuped by! the black-capped vreo were copperheads (Ancstrodon contor- trx), coachwhps (Mastcophs flagellum), kngsnakes (Lam- propelts callgaster), and blacksnakes (Elaphe obsolete). Though suspected predaton by snakes n a number of cases Ln whch nest contents dsappeared, wtnessed t only once Dn June 10, 1955» caught a blacksnake n the act of swallowng a nestful of young vreos whch were about nne days pld. The vreos reacted strongly toward coachwhps whenever phey saw them, scoldng and snappng ther blls. n Texas, found rattlesnakes (Crotalus atrox), coachwhps (Mastcophs taenlatus), green snakes (Opheodrys aestlvus), and patch-nosed snakes (Salvadora grahamjae) about the nestng areas of the vreo. Upon fndng a coachwhp n :he same bush n whch a black-capped vreo nest had recently peen robbed, klled the snake and found fve lzards n ts stomach. 131

145 132 Mammals seen n the Oklahoma study area were fox squrrels (Scurus nger), cottontal rabbts (Sylvlagus flordanus), rats (Neotoma sp.)» opossums (Ddelphs vrgnana), raccoons (Procyon l o tor), skunks (Mephts mephts), and red foxes (Vulpes fulva). One vreo nest was destroyed by a fox squrrel. Mammals other than rodents were not numerous n the area. n Texas, only rabbts (Sylvlagus flordanus and Lepus calforncus) and deer (Odocoleus vrgn anus ) were numerous. The vreos placed ther nests hgher n deer-browsed than n unbrowsed shrubbery. Brds whch occuped the same habtat as the blackcapped vreo n Oklahoma were the bobwhte (Colnus vrgnanus), mournng dove (Zenadura macroura), yellow-blled cuckoo (Coccyzus amercanus), roadrunner (Geococcyx calfornanus), chuck-wll's-wdow (Caprmulgus carolnenss), poorwl (Phalaenoptlus nuttall), downy woodpecker (Dendrocopos pubescans), Carolna chckadee (Parus carolnenss), tufted ttmouse (Parus bcolor), Bewck s wren (Thryomanes bewck), blue-gray gnatcatcher (Poloptla caerulea). Bell s vreo (Vreo bell), black and whte warbler (\notlta vara), prare warbler (Dendroca dscolor), yellowbreasted chat (ctera vrens), cowbrd (Molothrus ater), cardnal (Rchmondena cardnals), blue grosbeak (Guraca caerulea), panted buntng (Passerna crs), lark sparrow (Chondestes g r ammacus), and feld sparrow (Spzella p u slla)«

146 133 n Texas, the mournng dove, ground dove (Columbgallna passerna), ladder-backed woodpecker (Dendrocopos scalars), black-crested ttmouse (Parus atrcrstatus), Bew c k s wren, mockngbrd (Mmus polyglottes), blue-gray gnatcatcher, whte-eyed vreo (Vreo grseus). Bell's vreo, yellow-breasted chat, cowbrd, cardnal, panted buntng, house fnch (Carpodacus mexcanus), rufous-crowned sparrow (Amophla rufceps), lark sparrow, and feld sparrow were found n the same area as the black-capped vreo. n some localtes the scrub jay (Aphelocoma coerulescens), black and whte warbler, and golden-cheeked warbler (Dendroca chrysopara) and black-throated sparrow (Amphspza blneata) are found n the black-capped vreo's habtat. n Mexco (Coahula), the mournng dove, ladderbacked woodpecker, scrub jay, bush-tt (Psaltrparus mnmus), Bewck's wren, mockngbrd, gnatcatcher, black-headed grosbeak (Pheuctcus melanocephalus), house fnch, Mexcan goldfnch (Spnus psaltra), rufous-sded towhee (Pplo erythrophthalmus), and rufous-crowned sparrow occuped the black-capped vreo's habtat. Although the ecologcal nches of the black-capped. Bell's, and whte-eyed vreos meet and overlap slghtly, there apparently s no aggresson n ther competton. never wtnessed any fghtng between black-capped and whteeyed vreos whose terrtores clearly overlapped, or between Bell's and black-capped vreos on overlappng terrtores.

147 1 3 4 B ü n k ë (Ï^TO) Yëpôrt^sd"Tïndng a nest of the Bell s vreo and one of the black-capped vreo n the same bush. The two speces ( have never seen overlappng of terrtores of all three speces, though all three can be found n one localty land n such a localty terrtores of two of the three may overlap) appear to gnore each other, each gong about ts jdaly actvtes as f tne other were not present. found j ;. no evdence of nterbreedng between these speces. The habtats of Hutton s vreo (Vreo hutton) and the gray vreo (V. ve n or) dffer more from that of the black-capped vrecj 'than do those of the Bell s and whte-eyed vreos. n Coahula, Mexco, these fve vreos separate ncely nto dfferent levels and habtats. The Bell s occupes the mesqute lowlands between the mountans; the whte-eyed, more mesc lowlands; the gray, junper (Junperus monosperma) lowlands and low hllsdes; the black-capped, slopes at 3OOO to $000 peet covered wth low oak mottes; the Hutton s, the pnyon and pne level above that of the black-capped. The Hutton's and gray are western n dstrbuton, meetng the black- capped at the eastern edge of ther range. The whte-eyed s more eastern n ts dstrbuton, meetng the black-capped at the western edge of ts range. The Bell s has a wde, somewhat central, dstrbuton. seldom saw the black-capped vreo attack any other speces of brd. Once saw a male pounce on a blue-gray gnatcatcher, and another tme saw one fly at a feld

148 135 s o r r o w. ' Î Few brds of prey bother them. n three years tme, ; only one male nder observaton dsappeared durng the breedng season, and thnk t lkely that he may have met an ac** cdental death, as he had a roadsde terrtory and was n the habt of flyng across a busy hghway. The cowbrd s the speces greatest predator. On several occasons have seen ; a female vreo open her mouth n an aggressve manner at a female cowbrd that ventured near the nest whle the vreo! was on t. ; Covfbrds are defntely destructve as far as ths vreo s concerned. The greatest losses durng the nestng season are caused by cowbrds (see page 56). have seen a female cowbrd attack a nestful of young vreos so savagely that, had not ntervened, she would probably have klled one or more of the young brds. do not thnk that the cow- brd attacked the young to destroy the nest and thus brng about re-nestng a procedure suggested to occur n the old- world cuckoo (Cuculus canorus ) (Wtherby e_t ^., 91.8). Rather, beleve t was an attempt to drve a brd (the young were ten days old) off ts nest. The cowbrd could then nspect the nest for layng n the mornng (the attack took place at 6:20 p.m.). An ncdent of a cowbrd attackng h yellow warbler (Dendroca petecha) on ts nest has been reported (Hoyt, 19^8 ). The black-capped vreo s not very successful n

149 136 rearng cowbrds. Durng tbe course of ths study, only four cowbrd chcks were reared to the pont of leavng the nest, ' land saw none of these beng fed more than one day afterwards. When two cowbrd chcks are hatched n a nest, ne- : jther survves. Often the nest breaks loose from ts moorngs because of the weght of the chcks. f not, a predator gets the chcks. The food-cres of a large cowbrd chck attract predators. The vreos seem to be unable to adequately feed bwo cowbrd chcks n the nest or one large enough to leave the nest. The black-capped vreo does not bury the cowbrd under a new nest-floor as does the yellow warbler. found Dne nest n whch the cowbrd egg was partly bured but the cowbrd may have lad ths egg before the nest was completed. Hfhen a cowbrd egg s deposted before the nest-lnng s put n, the vreos usually add only a lttle materal as lnng.

150 CHAPTER X HABTAT! j Vegetaton of Breedng Habtat The black-capped vreo breeds n scrubby tree growth ^f the forest-grassland ecotone n the area of transton bej tween Merram s Austrorparan and Lower Sonoran Zones. The ;extent and heght of ths dwarf forest habtat s largely determned by clmatc, edaphc, and topographcal factors, but s also affected by secondary factors lke fre, grazng, and human dsturbance. Along the northern and western edge of the range sutable habtat occurs n ravnes whch provde more mesc cond t ons than the prare upland. On the eastern edge of the range weathered and eroded hghlands and stream boundares (above the flood plans) provde edaphc condtons for sutable vegetaton. Southward the habtat occupes hlltops jand mountan slopes to over 6OOO feet. Thus the black-capped vreo has been found n prare ravnes n Kansas, n canyons lke that of the Pecos Rver n western Texas, on eroded sandstone slopes n Oklahoma, on the hlls of the Edwards 13?

151 138 Plateau, and on mountansdes n Brewster County, Texas, and n central Coahula, Mexco. Areas supportng a clmax unsutable chefly because of sze and stand are rendered satsfactory by fre and cuttng of trees. have found black-capped vreos so often on burns that am convnced that the burnng practced by the ndans of the plans probably aded n the dspersal of ths speces. n recent tmes man has provded habtat by choppng down large trees, e.g., the cedars of the Texas hll country whch have formed brakes so dense no shrub understory could develop. Overgrazng has aded weatherng and eroson so that coarse sols favorng scrub growth have replaced rcher grassland sols. Browsng by goats, whch have been ntroduced n numbers n Texas wthn the last half century, reduces the habtat. Deer browse does not bother the brd (see page 132). Nests are frequently placed n cedar and evergreen sumac (Rhus vrens) n overgrazed pastures, as these plants are not eaten by cattle whch do browse on the small lve oaks (Quercus vrgnana). Human populaton pressure can drectly affect the black-capped vreo. atrcapllus s not a soltary speces; a populaton consstng of fve males and three females s the smallest breedng populaton have ever found. Snce each par requres about 3-4 acres, t appears that a mnmum of approxmately acres of sutable habtat s requred

152 139 for the brd to become establshed n any one place. Ths s more than s generally gven to natve shrub growth near any human dwellng. Then too, there s ncreasng dvson of land holdngs nto ever smaller plots, each of whch s treated dfferently, wth the result that there may be few areas of sutable habtat large enough to support a populaton of ths brd. n south central Texas, economy s forcng the change from large to small land holdng at a rapd rate. From north to south the plant speces formng the habtat gradually change. n the northern and eastern parts of the brd's range (Oklahoma, and northern and eastern Texas) predomnant tree speces are the blackjack oak (Quercus marlandca), post oak (Q. stellata), and red cedar (Junperus vrgnana). n the central part (Texas hll country), they are lve oak ( ^ vrgnana), Spansh oak (Q,. :texana), and mountan cedar (J^ ashe). n the southwestern part, they are varous scrub oaks (probably undulata, Q. ; texana or graves, Q. mohrana, Q. grsea, Q. ntrcate, and others), yuccas (Yucca spp.), and cornaceous shrubs (Garrya spp.). Junpers are few n the habtat n Coahula, Mexco. Varous knds of sumac (Rhus spp.) are mportant consttuents of the overall habtat. Woody plants now growng n parts of Comanche County, Kansas, beleved to have been nhabted by the vreo some years ago, nclude the red cedar, Amercan elm (Ulmus

153 lfo amerleana), gray dogwood (Cornus drummond), sumac (Rhus g l a b r a, Rhus trlobata), poson vy (Rhus toxcodendron), grape (Vts sp.)» woodbne (Parthenocssus qunquefola), chnaberry (Sapndus drummond), plum (Prunus spp.), currant (Rbes sp,), lead plant (Amorpha canescens), wafer ash (Ptelea trfolata), and walnut (Jugans ngra). A few oaks (Q. stellata, muhlenberg, and ^ macrocarpa) occur n some ravnes, but they are too large and too scattered to a f ford the type of growth preferred, and they probably have been so for more than a century. The brd probably occuped ravne slopes whch were covered wth small trees and shrubs of the speces lsted above. Ths type of habtat has been destroyed by drouth and cattle on all but the steepest and most shaded slopes. The Kansas type habtat merges n northern Oklahoma wth the cedar-oak (sometmes only oak) habtat so characterstc n that area and extends southward nto northern Texas. The speces and ther relatve mportance are ndcated n a detaled descrpton of my study areas whch follows. Mr. Geth Osborne and Mr. Edward C. Frtz descrbe the habtat on lmestone slopes n Dallas County, Texas, as secondary growth consstng of the followng speces: red cedar, post oak, turkey oak, red oak, lve oak, green ash, sumac (Rhus trlobata and Rj_ glabra), decduous holly (lex decdua), poson vy (R_, toxcodendron), black haw (Vburnum sp.), Forestera sp.. Prunus sp., woodbne (Parthenocssus qunquefola), and

154 kl cactus (probably Opunta sp.). The Oklahoma-type habtat merges wth that of the Edwards Plateau at about the lattude of Dallas as shown by the appearance of lve oak. Relcts of the Edwards Plateau vegetaton occur n the Arbuckle Mountans of southern Oklahoma. Post oak, blackjack oak, and cedar (the Oklahoma type habtat) occurs n the cross tmbers as far south as Bastrop County, Texas, and are found n the central gneous regon of Texas (Llano and surroundng countes). The habtat on the Balcones Escarpment of the Edwards Plateau s descrbed below. Ths type of habtat merges n Uvalde County wth that occuped by the brd n the south- westernmost portons of ts range. Trees and shrubs typcal of the Edwards Plateau occur as far west as northeastern Terrell County (Webster, 19^0 ). Speces typcal of the oak chaparral of Brewster County were found n Uvalde and Knney; Countes. Sotol (Dasylron texanum) and Mexcan persmmon (Dospyros texana), promnent plants n the habtat n Coahula, Mexco, are found on the Balcones Escarpment. The western lmts of the black-capped vreo appear to concde wth the eastern lmts of the gray oak (Q,uercus grsea) and oneseed junper (Junperus monosperma), though do not beleve that ths vegetaton tself halts the vreo. The character of the vegetaton does appear to lmt the eastern spread of ths brd, for the mesc forests of the eastern Unted States do not provde growth of the rght sze and

155 ll 2 arrangement. n southern Texas (Uvalde County), found black- capped vreos occupyng a habtat (burned over about seven years before) composed of the followng speces: Mexcan persmmon, mescalbean (Sophora secundflora), guajllo (Acaca berlander), buckthorn (Rhamnus carolnana), evergreen sumac, leatherplant (Jatropha spathulata), algerta (Berbers trfolata), and two chaparral oaks (Quercus spp.). A few larger trees of Spansh oaks, lve oaks, and Mexcan cedars (remnants of the domnant vegetaton) were also present. The habtat n northern Knney County, Texas, appeared to be smlar to that n the Glass Mountans north of Marathon. Cedar, scrub oak, lve oak, mescalbean, and evergreen sumac were major components. A few small pnyon pnes (Pnus cembrodes) and gray oaks were noted. n parts of the Glass Mountans these last named speces are common n the scrub growth. The vegetaton of the Glass Mountans has been descrbed by Sperry and Warnock (191^.1) The habtat n northern Terrell County, Texas, has been descrbed by Webster (19^0). The vegetaton of the slopes s lke that the upper slopes of the Pecos Rver gorge exhbt, wth the excepton of cedars whch are not found n the latter area. The persmmon-shn-oak assocaton appears to have provded sutable habtat, as well as the cedar-shn-oak assocaton n whch t was found by Thornton

156 W (1951) The cedar n the canyon floors s the habtat of the gray vreo, a very common speces here. Terrell, Brewster, Knney and southern Valverde countes are margnal areas for the black-capped vreo. n tmes when the clmate s favorable, these areas provde a habtat, but n perods of drought they do not. The habtat n Serra Padlla, Coahula, Mexco, appeared to be very smlar to that descrbed by Lesueur (19.5 ) for solated lmestone Serras (especally Serra del Pno) n northeastern Chhuahua. Accordng to Lesueur the lowest oaks appear at ^600 feet, and grow n dense mottes about one meter hgh. ^800 feet. The droopng junper (_J. flaccda) begns at From 6200 to 66OO feet a dwarf form of Q,uercus undulata s common and wth Ceanothus gregg, Garrya obovata, Fendlera lnears, Junperus flaccda forms an mpassable mat. n addton to the speces mentoned by Lesueur, noted (n the area occuped by black-capped vreo) Acaca berlander, Cercs sp., Dasylron texanum. Yucca sp., Rhus vrens. Mmosa sp., Quercus graves, and Quercus grsea. A few large pnes grew on solated rdges n ths range, but saw no pnyon pnes. n ths area Vreo atrcapllus was the common (and almost only) vreo. sav/ only one other vreo, a Hutton's vreo. The habtat n the Serra Madera n Coahula was smlar to that of Serra Padlla, but saw no redbud (Cercs sp.) there, and a fne pne forest covered the hgher

157 lll slopes. Ths range remnded me of the Chsos Mountans, and of the Serra del Carmen, as descrbed by Mller (19^5 )» Black-capped vreos were found only on dry, lmestone hllsdes where there were thck mats of vegetaton about three to fve feet n heght. n ths growth, Quercus undulata, and Rhus vrens were the most common woody plants. Also noted were: Molna sp.. Yucca sp., Dasylron texanum, Junperus flaccda. Prunus sp., Rhamnus sp., Garrya sp., Loncera sp., Bumela sp., and Arbutus texana. Ths shrub growth was most luxurant on slopes facng north and east. That whch examned on other slopes appeared to be half-dead from the drought. There was no surface water n ths range. The closest water, a small reservor whch suppled a few famles, was two mles from the Serra s base. The same stuaton exsted at Serra Padlla. Detaled Descrpton of the Oklahoma and Texas Study Areas n an effort to understand the breedng habtat requrements, made a count of the woody plants and estmated the sze of trees n quadrats encrclng most of the nests. These quadrats measured ^0 feet on a sde and were lad out by means of cord measured to that length. Snce most of the trees were not over 15 feet tall, an estmate of ther dameter was made at a heght of two feet above the ground (nstead of DBH). n the case of Junperus ashe whch branches near ts base, each lmb or trunk was consdered separately

158 11+^ jbo make possble ^comparson wth Junperus vrgnana. ~Data rom $1. quadrats n Oklahoma and 35 n Texas are presented. Data from one quadrat n Coahula are also presented, but plants collected n ths area have not been fnally dentfed. Frequency s consdered n Tables X and XV. n Tables XV and XV, data are presented on the sze and number of trees. beleve that these data are mportant because they further reveal the nature of the vegetaton n whch the black-capped vreo breeds. The woody plants are prncpally small, many-branched trees and shrubs that pro- vde good cover at near the ground. Some larger trees grow n the habtat. Ths unevenness of vegetaton s characterstc. have never found the black-capped vreo n oak shnnery cover of unform heght. The speces prefers mettez whch because of ther dstrbuton n.small thckets or clumps wth spaces between gve the landscape a "woolly aspect when vewed from a dstance. The vared from total number of shrubs and trees per quadrat 33 to 328 (average 122.3) n the Oklahoma study area. 2,6). n Texas, the number ranged from 6l to $68 (average n one quadrat n Mexco (Serra Padlla) the number was 71$. The vreo chooses a habtat n whch there s a consderable varety of woody plants. No fewer than 27 speces bf such plants grew n the Oklahoma quadrats. The average number of speces per quadrat was 7*8 (maxmum number, l6 ;

159 lj.6, FREQUENCY (N PERCENT) OP WOODY PLANTS N OKLAHOMA quadrats Speces Ffty-four quadrats (52 n Caddo Co., 1 n Dewey Co., 1 n Major Co.) Ffty-two Caddo Co. quadrats quercus marlandca quercus stellata Junperus vrgnana Qelts retculata Opunta sp. Rhus g'abra Symphorcarpos orbculatus Aesculus glabra Rhus toxcodendron Parthenocssus qunquefola Qercls canadenss quercus muhlenberg Bumela lanugnosa Prunus angustfola Rhus trlobata j[jlmus' *amer c ana Qornus drummond Juglans ngra Smlax bona-nox kmorpha canescens Yucca glauca Prunus mexcana Morus rubra Ptelea trfolata Forestera pubescens Cssus ncsa Vtls sp

160 r m a r x v FREQUENCY (N PERCENT) OF WOODY PLANTS N TEXAS QUADRATS 1! Speces All 3^ Quadrats Thrty-fve Quadrats n Hays and Comal Countes Fourteen Quadrats n Recently Burned Area Twenty-one Hll Countrj- Quadrats Quercus vrgnana Junperus ashe Dospyros texana Rhus vrens Quercus texana Berbers (both tr- 1 folata and swazey) Vts cnerea Rhus lanceolata Yucca rupcola Ce r c s ran f orms Smlax bona-nox ^ Mmosa boreals Bumela sp Chlopss lnears Rhus toxcodendron Opunta sp Quercus brevloba jprunus serotna 11.4 Porestera sp Rhus trlobata {Amorpha sp juhgnada s p e d os a Carrya lndhemer Ulmus crass f ola $ Lantana horrda 5» cssus sp ÎÜela azedarach Cocculus carolnus ptelea trfolata Loncera sp pelts sp Nolna sp prunus mexcana 2.8 1

161 TABLE XV NUMBER AND SZE OP LVNG TREES N PPTY-POUR OKLAHOvlA QUADRATS ( DATA) Speces Dameter n :nches at Two Pee t Under Over 10 Tota No. Quercus marlandca Quercus stellata Junperus vrgnana Celts retculata Aesculus Rlabra Quercus muhlenberg ; Cercs canadenss Bumela lanugnosa tjlmus amer c ana ljuglans ngra Prunus mexcana 1 1 -p- 03 All Speces Dead Trees or 3.7^

162 TABLE XV NUMBER AND SZE OP LVNG TREES N THRTY-FVE TEXAS QUADRATS N HAYS & COMAL COUNTES (1956 DATA) Speces Under 1 1 Dameter 2 3 n 4 nches 5 at 6 Two 7 Feet 8 9 Over Total N o. ' ; Quercus vrgnana Junperus ashe Quercus texana Cercs renforms loj. Quercus brevloba : Bumela sp : Prunus serotna tjlmus crass f ola ; Prunus mexcana : Celts sp. 1 1 ; All Speces ;

163 150 mnmum, j.). ' n all the' Texas qüahràts, a total of '33 "spe- ces grew (average number of speces per quadrat, 8.3; maxmum, 19; mnmum, 3 ), n two quadrats on an ungrazed burn area (not burned recently) the average number was 6.9 (maxmum, 13; mnmum, 3). n one quadrat n Mexco (Serra Padlla), l speces of woody plants were found. n the Texas quadrats n whch only two or three speces of woody plants were found, the cover was provded by cedar wth ever- green sumac understory, lve oak wth cedar understory, or lve oak wth evergreen sumac understory. n the two Oklahoma quadrats n whch only four speces of woody plants were: found, the cover was provded by blackjack oak and cedar, and : blackjack oak, post oak, and cedar. 1 One other feature of the habtat was consdered the age of the trees. As Beecher (19^2 ) has stated, an anmal populaton can be no more stable than the plant communty n!! whch t lves. n case of the black-capped vreo, the hab-l tat must reman sutable for a certan mnmum of tme, just! ; ' as there must be a certan mnmal area of sutable habtat ; f for a populaton to establsh and mantan tself. Further- more, an area n whch the vegetaton remans sutable for long perods provdes more avalable habtat than an area n Whch the plants grow faster. f the vegetaton n a certan localty remans sutable for 30 years, the area provdes fve tmes as much habtat as one n whch the woods becomes too large n sx years.

164 151 n the Oklahoma study area, red cedars 9-10 feet hgh and wth basal dameters of 2 to 3 nches were estmated, by countng growth rngs, to be 18 to 19 years old. ths sze were found to be 12 to 3Ô years old. Oaks of A buckeye shrub (Aesculus glabra) 6 feet hgh wth basal dameter of 2 nches was estmated to be 13 years old. Pumac (Rhus glabra) 5 feet hgh, wth basal dameter of 5/3 nch was 5 to 6 years old, ths plant havng grown snce the last burn n the area seven years prevously. Two oaks (g^ undulata) from Serra Madera wth basal dameters of one nch had 19 growth rngs. On burns wthn the man part of the vreo's range (Texas and Oklahoma), shrub growth can attan a heght of two to three feet n three years (f condtons are usual). From ths stage, growth s slow, probably because of the shallowness of the sol whch lmts the mosture avalable to plants. Black-capped vreos are most often found on steep slopes, smply because the woody growth remans a sutable sze for longer perods than t does n areas where there s more sol. Rugged terran provdes many mcro-clmates and vared edaphc condtons so that the vegetaton grows rregularly, formng clumps. Plat land tends to grow forest or prare dependng on clmate and sol. Only n a very lmted area (prare-forest ecotone) can vacllatons n clmate produce dwarf forests on flat land, and such shnnery, because of the evenness of ts heght and arrangement, s seldom attractve to black-capped vreos. nstead the brd seeks

165 152 ravnes whch can provde the condtons mentoned above. More habtat may be produced by the vacllatons n clmate, provded these are not severe. The vegetaton must be dstrbuted over certan area (a spatal requrement), not arranged lnearly n rows or strps as wth roadsde shrubbery. The black-capped vreo sometmes nests on the roadsde, but only when a sutable area adjons the roadsde. The speces does not utlze roadsde edge as does the Bell's vreo. Vegetaton of the Wnterng Habtat The wnterng habtat (see Fgures 3-16) s dffcult to descrbe. The requrements of the speces apparently are less strct n the non-breedng season than n the breedng, and so there s a wder range of vegetatonal types n the wnter habtat than n the summer. n southern Snaloa (near Concorda, whch les just east of Mazatlan, n the frst foothlls of the Serra Madre Occdental), the wnter habtat was ard scrub 2-10 feet n heght. Promnent among many woody speces were Ardesa revoluta, Bursera sp.. Mmosa sp., and pomoea ntraplosa. Large cact (columnar cereus) were nterspersed throughout the woodland. When was there (December) few of the trees had leaves, though some were flowerng, especally pomoea. The aspect was not unlke the breedng habtat n Texas at about arrval tme. The habtat n Hayart (near Las Varas on the coast

166 1 ^3 yvest of Compostela) the wht'er'habtat was more mesc and luxurant than that of Snaloa. Here the brd chose cut-over sad secondary growths that were composed of an ncredble mxture of woody plants, palmettos, palms, cact of varous types, and mmosa. Especally prevalent were Combreturn farnosum, and the large leaved shrub, Bxa orellana. Thckets of the latter appeared to be especally favored by the black-capped vreos. Ths habtat seemed dfferent (except for ts shrubby nature) from any n whch had found the vreo, and suspect t s a secondary habtat whch has become avalable only n the wake of cuttng and clearng. Clmate! Clmatographc studes of the breedng area should ; provde ndces of condtons most sutable to the physologcal requrements of a brd speces, snce the young have less tolerance than adults; the crtcal perod s the nest- lng perod; extremes at other tmes may not affect the speces; local dsturbances can dslodge a speces from margnal habtat; habtat that s sutable n "good" seasons can become ntolerable n "bad"; speces havng a narrow range of tolerance do not readly adapt to new envronments (Twomey, 1936). To ascertan how temperature and precptaton mght nfluence the dstrbuton of ths vreo, clmatographs were prepared usng data suppled by the Unted States and Mexcan

167 l ^ k patkèr Bureaus (19$6 ] r ta-f plaatologco de Mexco 1939)* Long term monthly means for Aprl, May, June, July, and August were plotted on the graphs as Aprl 1, June 2, etc. Clmatographs were prepared for thp wnterng area also, usng monthly means (the average of lj. years, ) for September through March, numberng the months on these maps as September 1, October 2, etc. n Graph V, Clmatograph A, lyng wthn B, represents data for Kerrvlle, Texas. Ths localty was chosen because the black-capped vreo has long occuped t contnu- : ously and successfully. t les n the central porton of the breedng range, and snce ts weather data appears to be close to the mean of all areas n whch the brd breeds, t probably represents the optmum condtons. Clmatograph B,! yh ch encrcles A, s based on localtes now occuped by the j vreo: Anadarko, Oklahoma; Boerne, Uvalde, Dallas, Waco, and Austn, Texas. Encrcled ponts are from these localtes. ; j Other ponts are from localtes n whch the vreo has been ' known to occur (and breed): Cmarron, Jetmore, Medcne. Lodge, and Wnfeld, Kansas; Apache, Tulsa, and Oklahoma Cty, Oklahoma; and Juncton and San Angelo, Texas. Aprl temperatures were omtted for Jetmore, Cmarron, Medcne Lodge, and Wnfeld, Kansas, and for Tulsa and Oklahoma Cty, Oklahoma. The brd does not arrve untl late Aprl n these places, so they may be dsregarded. Clmatograph B represents the lmts of ranfall and temperature n localtes n

168 155 GRAPH V^ '... TEMPERATURE AND PRECPTATON N BREEDNG HABTAT Aprl-September monthly means of precptaton n nches

169 1^6 whch the vreo regularly breed's. Ponts' dut'stde of B"^are.. from localtes occuped when clmatc varaton alters them : to fall wthn the brd's habtat requrements. Graph V depcts ranfall and temperature at Kerrvlle, Texas, and at several localtes just west of the western lmts of the breedng area. The Davs Mountans n Jeff Davs County, Texas, and the Glass Mountans near Alpne, n northern Brewster County, Texas, have shrubby hab- ' tat whch appeared to be sutable for breedng, but saw no brds there n 195b and 1956* Graph V suggests that west- : ern lmts of breedng are determned by coolness and dryness. Ths pcture s based on long term means. n some perods the clmate may allow the vreo to become establshed, but n general t s unfavorable. Here clmate tself, rather than vegetaton, appears to be the lmtng factor. : Graph V compares precptaton and temperature of three localtes to the north and east of the brd's range wth that at Kerrvlle. Lack of sutable habtat, rather than clmate, lmts the vreo n ths drecton. Greater amount of precptaton ndrectly affects the dstrbuton because the vegetaton grows too rapdly and becomes too large to provde acceptable habtat. At present, drought condtons have brought about a reducton n the breedng range, especally n the north and ; west. n » the vreo bred n southern Kansas and western Texas (San Angelo). Kncer has depcted a gradual

170 157 GRAPH V... TEMPERATURE AND PRECPTATON N WESTERN TEXAS AND WESTERN OKLAHOMA Kerrvlle, Texas B Alpne, Texas C Lubbock, Texas D Bose Cty, Oklahoma Mt«Locke, Davs Mts«, Texas h & 5 1 Monthly mean precptaton n nches

171 158 GRAPH V.... TEMPERATURE AND PRECPTATON N LOCALTES NORTH AND EAST OF THE BREEDNG AREA AND THOSE AT KERRVLLE, TEXAS 65 T 76 \2 53 A Kerrvlle, Texas B Omaha, Nebraska C Manhattan, Kansas D Houston, Texas 3 ss Z Monthly mean precptaton n nches

172 1^9 decrease n precpaïîdn am' angne re as^e n Temperatures.. snce 9O (Tannehll, 19^7 ). Between 18^0 and 9O ranfall was greater and temperatures cooler (Bownad, 1935)» But though the vreo occupes a zone of transton between humd and dry clmates, a zone n whch fluccuaton s characterstc (Kendall, 1935)» long term trends toward ardty appear to have a pronounced effect on ts dstrbuton. Graph X depcts September-to-larch temperature and precptaton on the wnterng grounds. Lne C represents condtons (monthly means numbered) at San Bas, Nayart, Mexco, a localty havng ntermedate poston and clmate. Enclosure A represents the range of condtons from Cudad Obregon, Sonora, to Acapulco, Guerrero, Mexco, and from sea level to 3011 feet (Tepc, Nayart). Enclosure B (as n Graph V) represents the range of condtons on the breedng grounds n Texas and Oklahoma from Aprl to September. Lne ; D ndcates the lmts of most of the localtes of the wnterng grounds (the larger enclosure ncludes Cudad Obregon, Sonora). Localtes ncluded n preparng A are: Cudad Obregon, Sonora; Mocorto, Culacan, and Mazatlan, Snaloa; ; Acaponeta, Tepc, and San Bas, Nayart; Manzanllo, Colma;! and Acapulco, Guerrero. Durng most of the wnter the wnterng grounds are much more ard than the breedng grounds. Only n September ^ and October s there as much or more ranfall than n the breedng area. Ths ardty can be endured because t

173 6o GRAPH ÎX TEMPERATURE AND PRECPTATON OF WNTERNG AND BREEDNG HABTATS Wnterng Summer (breedng) San Bas, Nayart 80--J / V September (not show) October November December January February March îfonthly mean precptaton n nches

174 6 follows a rany season, thus bengqute dfferent than f t were a drought or desert condton. On the breedng grounds t would affect the vegetaton because a large porton of the annual precptaton occurs durng sprng and summer. Monthly means of ranfall n the area nhabted vary from 0.0 to 6 (possbly 10) nches. Mosture s frequently provded n the form of fog along the coastal lowlands of Mexco. The temperature lmts of the breedng and wnterng grounds are about the same, monthly means fallng between 60 and 87 F. #en was n Mexco n late December 195^» recorded the maxmum temperatures at 8^-98^ F. near Concorda, Snaloa, and at 86 F. at Las Varas, Nayart. Daly mnmums were $8-62 F. near Concorda, and $1-$1 F. at Las 1 Varas. The cooler nght temperatures at the lower elevaton (Las Varas) were brought about by coastal fogs. These re- ;Cordngs were taken n the feld at the places saw black- ; capped vreos wnterng. The U.S. Weather Bureau provded the followng data: Localty Wnter Temperature Extreme Hghest Extreme Lowest ; Acapulco 97 (Oct.) 60 (Feb.) Campeche 95 (Mar.) (Feb.) Mazatlan 92.1 (Sept.) 52.2 (Jan., Feb.) Culacan loj. (Sept.) 38 (Jan.)

175 162 The northern lmts of the wnterng grounds are probably set by low extremes of temperature. The brd appears to prefer temperatures well above freezng, though t can wthstand bref cold spells. t s relatvely heat tolerant. The wnterng and breedng grounds do not have greatly dfferng clmates. The more varable factor, ranfall, hp.s broader lmts n the wnter. The black-capped vreo has a narrow range of clmatc tolerance, and ts dstrbuton s relatvely lmted, suggestng that t does not adapt readly to new envronment. have wtnessed halstorms, ranstorms, dust storms, and hgh wnds whle observng the black-capped vreos, but have never seen any losses of eggs, young, or adults because! of unusual weather. Bunker (1910) reports loss of eggs from : nests followng a severe storm.

176 CHAPTER X DSCUSSON The black-capped vlreo s dstnctve, as a speces of the genus Vreo, n that ts plumage color exhbts pronounced sexual dmorphsm, ts eggs are pure whte, and ts song s composed of extremely varable phrases. A wnter head molt, whch may also be dstnctve, may be an aspect of sexual dmorphsm. The speces appears to be not prmtve, but hghly specalzed. t may be of recent or of very ancent orgn. No factor was found n the lfe cycle that could ac- : count for ts lmted numbers. ts habts are smlar to those of other vrecs. ts nestng success s low compared to that of other passernes, but not lower than that of a closely related, more wdely dstrbuted speces of vreo, Vreo bell. The black-capped vreo suffers large reproductve losses because of cowbrd parastsm, but so does Bell s vreo. The black-capped vreo s low reproductve success s probably compensated for by the survval rate and longevty of adults. The speces appears to be as long-lved as certan more wdely dstrbuted forms {Hann, 19lj.8; Nce, 163

177 l6f Vreo atrlcapllus appears to be unusually free of ectoparastes and dsease. Loss durng breedng season may have amounted to one adult from 1^0 brds n three seasons' observatons. Few, f any, predators take adult vreos. Vreo atrcapllus does not appear to be restrcted by det. Food found n the stomachs of 11 specmens was smlar n type and amount to that found n stomachs of the Red-eyed Vreo (Chapn, 1925). nterchange of young black- capped and Bell's vreos showed that each of these could subsst as nestlngs and fledglngs on the food of the other. A captve fledglng atrcapllus throve on a varety of nsects. Presence of surface water does not account for the black-capped vreo's localzed dstrbuton. The brd lves n some stuatons where no water, other than that present n ts food or resultant from occasonal precptaton, s avalable. The habtat provdes good shelter and cover. No loss of any knd resulted from ran, wnd, hal, or severe dust storms that occurred durng my observatons. The brd s lmted by a narrow range of temperature tolerance. t does not occur n areas n whch the temperature falls below a certan pont. Ths probably explans why the speces has not spread northward or nto the mountans. The sze and arrangement of vegetaton appears to be

178 6$ mportant. The type of woody plants s mportant. Throughout the brd's breedng range several dfferent plant (speces) assocatons are found, but these assocatons ntergrade wth each other, and ther members may be consdered as ecologcal counterparts. The type of vegetaton occuped occurs very locally throughout the area n whch the clmate s sutable, perhaps explanng the brd's localzed dstrbuton. t has occuped all the avalable habtat and apparently does not adapt to other habtats.

179 CHAPTER X SUMMARY 1. Vlreo atrcapllus mgrates northward n sprng, arrvng n the southern part of the breedng grounds n March, n the northern part, n late Aprl. 2. The male establshes a terrtory of two and one-half to four and one-half acres by song and pouncng. All actvtes are carred out on ths terrtory. ndvdual brds return to the same terrtores year after year. 3. Mates may be changed between broods or between seasons, but usually a par remans together for a season. The female s courted by song and dsplay, l-. Nests are placed n crotches of lmbs one to four feet above the ground. Oaks are usually chosen. There s a tendency for vreos to re-use nest stes season after season. 5. The nest s typcally vreonne. t s bult of materals avalable nearby, and both male and female partcpate n nest-buldng. Constructon may take as lttle as four days or as much as 16 days. 6. Layng occurs at about 6:00 a.m. (durng June, n 166

180 167 Oklahoma) on consecutve days. The peak of layng s n May n Texas and n June n Oklahoma. 7. A clutch conssts of three or four eggs. The eggs are whte, mmaculate, and average approxmately 17.6 x 3. mm. They wegh about l.s grams. 8. ncubaton begns after the layng of the second or thrd egg. n general the parent brds ncubate alternately throughout the day. The female ncubates at nght. The ncubaton perod vares from lj. to 17 days. 9. At hatchng, the chck s completely naked and blnd, and weghs about one gram. t gans about a gram a day untl t weghs seven or eght grams. ts feathers unsheath on the eghth day. t leaves the nest at 10 to 12 days. \ ' The postjuvenal molt begns at the age of two weeks. Forty-four days after leavng the nest, one young brd was ndependent of ts parent. 10. The young n the nest are cared for by both male and female adults. The female does all the broodng. The male brngs about three-fourths of ther food to the young. Fledglngs are cared for by both parents for four to seven days, then the female begns another nestng. She ether does all the ncubaton and cares for the young of the second brood or gets another male to help her, her frst mate beng occuped wth the care of the fledglngs. 11. The young are fed 0.8 to 2.6 tmes an hour. As the young grow, the number of trps the adults make to brng food

181 l68 to them remans the same, but larger tems are brought. One cowbrd chck requres as much food as four vreo chcks. 12. A black-capped vreo egg placed n the nest of a Bell's vreo (Vreo bell) hatched and the young brd was reared by ths foster parent. Lkewse, a Bell's vreo was reared by a black-capped vreo. 13. Of 2j.3 eggs, j.3 (17*6^) were successful to the stage of nest-leavng. Of 75 nests, l5 {20%) were successful n producng one fledglng. n the breedng season. A survey of pars was made late Of 77 pars, l\.$ were successful n fledgng at least one young brd. l. The greatest losses n eggs and young were caused by cowbrd actvty. Nnety-seven eggs (72.3^ of those lost), ; and 2^ (29.7^ of the vable chcks) chcks were lost be- ; cause of cowbrds. The Bell's vreo appears to sustan such losses also. l^e Fall mgraton begns n August. The earlest known arrval on the wnterng grounds s August 27th. No black- capped vreos have been seen on the breedng grounds after September. 16. Between $0 and 60 per cent of the breedng brds were new to the Oklahoma study area each season. Between 75 and 80 per cent of the banded males returned for a second season, but only 33*3% to ^1.6^ of the females returned. The dfference may be accounted for by the elusveness of

182 1 6 9 the female and by falure of the female to return to the same area. Twenty-nne per cent of the banded brds returned for a thrd season (lj.1.6^ of the males, l6.6^ of the females). One par (8.6^) of 23 brds trapped n 1955 were brds breedng for the frst tme. 17. The sex rato vared from 100 (males) ; 100 to 131:100. A few males dd not fnd mates durng some seasons. 10. The habts of ths vreo are smlar to those of other vreos. Ths speces s very actve, roosts soltarly, and was observed to bathe n water. ts song s the most complcated wthn the genus Vreo. t has at least four dfferent songs and gves several other sounds. 19. The food found n stomachs of eleven specmens was smlar to that found n stomachs of other vreos by Chapn. The bulk of the food s composed of larvae of Lepdoptera and of small Coleoptera. n fall and wnter, some seeds are eaten. The brd can apparently lve n regons where there s no surface water. 20. No ectoparastes were found on any vreo or n any of ther nests. No brds appeared to be dseased. 21. The age and sex of an ndvdual are ndcated by plumage. Northern adult males are slghtly larger than southern adult males (a sze dne). Males are larger than females. Older brds tend to be larger than younger brds. The juvenal plumage and the molts are descrbed. A pecular molt on the head occurs n November, so that

183 170 all males have darker heads than females by breedng season. 22. Vreo atrcapllus breeds locally from north central Oklahoma, through central Texas, to north central Mexco (Coahula). t wnters on the west coast of Mexco from southern Sonora to Guerrero. n the breedng area t s usually found at elevatons of 1,000-2,000 feet, but may occur at ^,^00-6,000 feet n the southern part of ts range.. n wnter t occurs at elevatons from sea level to about 3,000 feet. 23. The breedng range at present s smaller than t was around 9OO. Long term trends toward hgher temperatures and less precptaton may account for a reducton n the habtat at the western and northern edges of the breedng range. 24. A lst of other vertebrates found on terrtores of black-capped vreos s gven. The ecologcal relatonshps of V. bell, V. grseus, V. hutton, and V. vclnor are brefly dscussed. 25» Vegetaton of the habtat was studed n two areas n whch the speces s successful, and n areas at the edge of the brd s range. The speces prefers scrub-oak growth of rregular heght and dstrbuton. The habtat must cover a rectangular, rather than a lnear area. Eroded slopes often provde edaphc condtons whch favor such habtat.

184 # n % r y means'o-f ^ e W e r a m r e ^ ^ tre! brd (both n summer and wnter) were between 63 and 87 F. Extreme lows of temperature were well above! freezng (37 P.)» Monthly means of precptaton were between zero and fve nches. Precptaton s mportant! ndrectly because of ts effect on vegetaton. 27. The black-capped vreo appears to be lmted n ts ds- ; trbuton by rgd requrements of vegetatve and cl- ; matc factors. t does not adapt to modfed condtons ; and therefore becomes very lmted n ts dstrbuton.!

185 BBLOGRAPHY Attwater, H» P A lst of Brds Observed n the Vcnty of San Antono, Bexar County, Texas. Auk, 9 î340*3^+1 Baley, P. M Handbook of Brds of the ïvestern Unted States. (Houghton Mffln & Co., Cambrdge, Mass.) Bard, S. P Brds. Exploratons and Surveys for a Ralroad Route from the Msssspp Rver to the Pacfc Ocean. War Department. Washngton, D.C. 1874» Revew of Amercan Brds n the Museum of the Smthsonan nsttuton Smthsonan Mscellaneous Collecton, 12. Brewer, T. M., and Rdgway, R. 1874' A Hstory of North Amercan Brds. Land Brds, 1. (Lttle Brown and Co., Boston.) Baumgartner, P. M. 1944' Unusual Records for North Central Oklahoma. Wlson Bulletn, $6 :ll6. Beecher, W. J. 1942» Nestng Brds and the Vegetatve Substrate. (Chcago Ornthologcal Socety, Chcago, 111.) Benners, G. B A Collectng Trp n Texas. The Ornthologst and Oologst, 12: Bent, A. C. 1950' Lfe Hstores of North Amercan Wagtals, Shrkes, Vreos, and Ther Alles. U. S. Natonal Museum Bulletn, no. 197' Bowman,. 1935' Our Expandng and Contractng "Desert." Geographcal Revew, 25:

186 173 Bray, W. L The Vegetaton of Texas. Unversty of Texas Bulletn, no. 82. Brewster, W. 1879' Notes Upon-the Dstrbuton, Habts, and Nestng of the Black-capped Vreo (Vreo atrcapllus). Bulletn Nuttall Ornthologcal Club, lf:99"103' Brown, N. C A Reconnassance n Southwestern Texas. Bulletn Nuttall Ornthologcal Club, 7:33-42* Brunner, L Some Notes on Nebraska Brds. (State Journal Co., Lncoln, Neb.) Bunker, C. D Habts of the Black-Capt Vreo (Vreo atrcapllus). Condor, 12:70-73» Burktt, J. P A Study of the Robn by Means of Marked Brds. Brtsh Brds, 20: Cassn, J. l8o2. llustratons of the Brds of Calforna, Texas, Oregon, Brtsh and Russan Amerca. (J. P. Lppncott & Company, Phladelpha, Pa.) Chapn, E. A. 1925» Food Habts of the Vreos. U. S. Department of Agrculture Bulletn, no. 13^^. Chapman, F. M Color Key to North Amercan Brds. (Doubleday, Page & Company, New York, N. Y.) Cooke, W. W Report on Brd Mgraton n the Msssspp Valley n the Years l88.-5 ' (Government Prntng Offce, Washngton, D.C.) The Mgraton of Vreos. Brd-Lore, 11: , Plate opposte p Cory, V. L., and Parks, H. B. 1937' Catalogue of the Flora of the State of Texas. Bulletn Agrcultural and Mechancal College of Texas, no. 5^ 0 *

187 174 Coues, E Brds of the Colorado Valley. Mscellaneous Publcaton No. 11, Department of the nteror, U.S. Geologcal Survey of the Terrtores, Part Key to North Amercan Brds. (Estes & Lauréat, Boston, Mass.) 1879» Note on the Black-capped Greenlet, Vreo atrcapllus of #oodhouse. Bulletn Nuttall Ornthologcal Club, 4 : » Cruckshank, A. D. 19^0. Records from Brewster County, Texas. Wlson Bulletn, 62: Davs, Nests and Eggs of North Amercan Brds, ^th ed. (Landon Press, Columbus, Oho.) Deane, H. 1879* Vreo atrcapllus n Texas. Bulletn Nuttall Ornthologcal Club, 4 :^8-$9 * Douthtt, B. P. 1919* Mgraton Records for Kansas Brds. Wlson Bulletn, 31:6-20. Dwght, J., Jr The Sequence of Plumage and Moults of the Passerne Brds of New York. Annals of New York Academy of Scence, 8:73-3oO, "Elanodes" Lst of the Brds of McLennan Co., Texas. The Ornthologst and Oologst, 15:57-59» Ely, C. A. 1957' "Comparatve Nestng Success of Certan South Central Oklahoma Brds." Master s thess at Unversty of Oklahoma. Force, E. R The Brds of Tulsa County, Oklahoma, and Vcnty. Proceedngs Oklahoma Academy Scence, 9 :67-72.,and Hughes, W. 1940» Tme Table of Brds of Tulsa County, Oklahoma and Vcnty. (Tulsa Audubon Socety, Tulsa, Okla.)

188 175 Goss, N. S The Black-capped Vlreo and Konparel n Southwestern Kansas. Auk, 2 :27^-27o. Graham, R Brds That Nest n Tarrent fscl County, Texas, and Notes. The Oologst, 32:191. Hann, H. W. 19^8. Longevty of the Oven-brd. Brd-Bandng, 19:5-32. Headstrom, R. 1951» Brds' Nests of the West. (ves Washburn, nc., New York, N.Y.) Hellmayr, C. E Catalogue of Brds of the Amercas. Feld Museum Natural Hstory Publcaton, no. 3^7. Hensley, M Notes on the Breedng Behavor of the Bell's Vreo. Auk, 67:2^3-2^^. Herrck, P. H Home Lfe of Wld Brds. (G. P. Putnam's Sons, New York, N.Y.) Hoyt, J. S. Y. 19^8. Cowbrd Attacks Yellow Warbler on Nest. Auk, 65: Kelley, C Brds of Dallas County, Texas. Amercan Mdland Naturalst, 16:93^-9^8. Kendall, H. M Notes on Clmatc Boundares n Eastern Unted States. Geographcal Revew, 25:117-12^. Kendegh, S. C The Role of Envronment n the Lfe of Brds. Ecologcal Monographs,.:299-^17. 19^2. Analyss of Losses n the Nestng of Brds. Journal of Wldlfe Management, 6 : Kncad, E. B., Jr. 1954* Texas Ornthologcal Socety Bulletn, no. 2.

189 176 Kncer, J. B The Clmates of the Great Plans as a Factor n ther Utlzaton. Annals of the Assocaton of Amercan Geographers, 13: Krn, A. J., and Qulln, R. W Brds of Bexar County, Texas (checklst). (Wtte Memoral Museum, San Antono. Texas.) Lacey, H The Brds of Kerrvlle, Texas and Vcnty. Auk, 28: Lawrence, G. N. 187^, Brds of Western and Northwestern Mexco. Memors Boston Socety Natural Hstory, 2:ll6-13^. Lawrence, L. K. 9S3. Nestng Lfe and Behavor of the Red-eyed Vreo. Canadan Feld-Naturalst, 67:^7-77* Lesueur, H. 19^^. The Ecology of the Vegetaton of Chhuahua, Mexco, North of Parallel Twenty-eght. Unversty of Texas Publcaton No. j.521. Lloyd, W. l88[. Note. The Ornthologst and Oologst, 9 :10^-* Brds of Tom Green and Concho Countes, Texas. Auk, 4.: MacMllan, R. A., and Eberhardt, L. L. 19^3. Tolerance of ncubatng Pheasant Eggs to Exposure. Journal of Wldlfe Management, 17: Mller, A. H. 19^5 * The Avfauna of the Serra del Carmen of Coahula, Mexco. Condor, 37:15-^ Moore, R. T Unusual Brds and Extenson of Ranges n Sonora, Snaloa, and Chhuahua, Mexco. Condor, [}.0; Morse, G. 'W Notes on the Black-capped Vreo. The Oologst, 4.4.: 2 3» (Breedng) Brds of Tulsa, Oklahoma. The Oologst, ^6:80-81.

190 177 Mumford, R. E Bell s Vreo n ndana. Wlson Bulletn, 64^ WehrlnR, H Our Natve Brds of Song and Beauty. Vol. 2. (George Brumder, Mlwaukee, Ws.) Nce, M. M, 1929» Vocal Performances of the Rock Sparrow n Oklahoma. Condor, 31: The Fortunes of a Par of Bell's Vreos. Condor, 31: Brds of Oklahoma. Bologcal Survey, Vol. 3, Unversty of Oklahoma, Norman, Oklahoma Studes n the Lfe Hstory of the Song Sparrow.. Transactons of the Lnnean Socety of New York, 4 Î Peterson, R. T A Feld Gude to the Brds (Eastern Unted States). (Houghton Mffln Co., Boston, Mass.) Phllps, J. C A Year s Collectng n the State of Tamaulpas, Mexco. Auk, 28: Ptelka, F. A.j and Koestner, E. J Breedng Behavor of Bell's Vreo n llnos. Wlson Bulletn, 54 :97-106, Putnam, L. S The Lfe Hstory of the Cedar Waxwng. Wlson Bulletn, 6l:l4l-l82. Ragsdale, G. H.! 880. Addtonal Notes Concernng the Black-capped Vreo n Texas. Bulletn Nuttall Ornthologcal Club, 5 :239. Renardo, J Notes on Some Brds of the Unted States Whch Occur n the Mexcan Fauna. The Ornthologst and Oologst, 11: Rdgway, R The Brds of North and Mddle Amerca. Part. U.S. Natonal Museum Bulletn, no. 50»

191 178 Russell, R. -J. 19l 5 «Clmates of Texas. Annals of Assocaton of Amercan Geographers, 3^:37-^2. Schultze, A. E The Summer Brds of Central Texas. (A. E. Schultze, prvately prnted, Austn, Texas.) Selle, R. A. 1933» Brds Sng n Houston. Outdoor Nature Seres. (Carroll Prntng Co., Houston, Texas.) 193^' El Jardn, Brds Sng n Texas. Outdoor Nature Seres. (Carroll Prntng Co., Houston, Texas.) Smmons, G. P Brds of the Austn Regon. (Hnversty of Texas Press, Austn, Texas.) Sngley, J. A Observatons on Eggs Collected n Lee County, Texas, etc. The Ornthologst and Oologst, 12:163-16$. Smth, A. P Addtons to the Avfauna of Kerr County, Texas. Auk, 33: Some Texas Brd Notes. Condor, 20:212. Sperry, 0. E., and Warnock, B. H. 19^1. Plants of Brewster County, Texas. Sul Ross State Teachers College Bulletn, Vol. 22. Stager, K. E. 19$^. Brds of the Barranca de Cobre Regon of Southwestern Chhuahua, Mexco. Condor, $6 : Stephens, T. C A Study of a Red-eyed Vreo Nest Whch Contaned a Cowbrd s Egg. Bulletn Laboratory of Natural Hstory, 7 :2$-37«(Unversty of owa, Des Mones, la.) Stewart, R. E., and Aldrch, J. W. 19$1. Removal and Repopulaton of Breedng Brds n a Spruce-Pr Forest Communty. Auk, o8;^71-^82. Stllwell, J. E Checklst of tne Brds of Dallas County, Texas. (Boyd Prntng Co., Dallas, Texas.)

192 179 SÆr ectee^""*"jr lcr; Jr The Brds of Texas: an Annotated Checklst. (Baylor Unversty, W'aco, Texas.) The Ornthology of McLennan County, Texas. Baylor Unversty Museum Specal Bulletn, no. 1, Waco, Texas. Studer, J. H Popular Ornthology, The Brds of North Amerca. ; (J. H. Studer & Co., New York, N.Y.) Sutton, G«M Breedng Brds of Tarrant County, Texas. Annals of Carnege Museum, 27: Swenk, M. 1919* The Brds and Mammals of Nebraska. (Unversty of Nebraska, Lncoln, Neb.) Tannehll,. R.! 19^7» Drought, ts Causes and Effects. (Prnceton Unversty Press, Prnceton, N.J.) Thornton, W. A. 1951» Ecologcal Dstrbuton of the Brds of the Stockton Plateau n Northern Terrell County, Texas. Texas Journal of Scence, 3 :^13-^30. Tordoff, H. B. 19SO' Checklst of the Brds of Kansas. Unversty of! Kansas Museum of Natural Hstory Publcaton, 8: Twomey, A. C Clmatographc Studes of Certan ntroduced and Mgratory Brds. Ecology, 17: jvan Hoose, S. G Dstrbutonal and Breedng Records of Some Brds : from Coahula. Wlson Bulletn, 67: [Van Tyne, J., and Sutton, G. M. 1937* The Brds, of Brewster County, Texas. Mscelj laneous Publcaton No. 37» Unversty of Mchgan Museum of Zoology, Ann Arbor, Mchgan.! Webster, G. L. 19$ 0. Observatons on the Vegetaton and Summer Flora of the Stockton Plateau. Texas Journal of Scence, 2 : ;

193 180 Wheelock,. G. 1905» Régurgtât!ve Feedng of Nestlngs. Auk, 22 Wtherby, H. F., Jourdan, F. R. C., Tcehurst, N. C., and Tucker, B. W. 19^8. Handbook of Brtsh Brds. Vol.. (H. F. and G. Wtherby Ltd., London, England.) Woodhouse, S. D. 18^2. Descrptons of New Speces of Brds of the genus Vreo, Vell., and Zonotrcha, Swans. Proceedngs of the Academy of Natural Scences of Phladelpha, 6:60. S^j-. Stgreaves Report of an Expedton Down the Zun and Colorado Rvers. Secton on Brds, 6 : (Washngton, D.C.) Yocum, H. A. 193!? Tulsa, Oklahoma, Nestng Dates. The Oologst, 52 :.0-fl.

194 APPENDCES

195 APPENDX Lst of Abbrevatons Used for Museums and Natural Hstory Collectons: AMNH Amercan Museum of Natural Hstory, New York, N.Y. ; BM BU Brtsh Museum (Natural Hstory), London, England. Strecker Museum at Baylor Unversty, Waco, Texas. CAS Chcago Academy of Scences, Chcago, 111. CNHM Chcago Natural Hstory Museum, Chcago, 111. j fc)m Carnege Museum, Pttsburgh, Pa. j CU Cornell Unversty (collecton), thaca, N.Y. j j pmnh Dallas Museum of Natural Hstory, Dallas, Texas. HM Hastngs Museum, Hastngs, Nebraska. KSHS Kansas State Hstorcal Socety (collecton), Topeka, Kansas KU Museum of Natural Hstory, Unversty of Kansas, Lawrence, Kansas. 1 LACM Los Angeles County Museum, Los Angeles, Cal. LSU Museum of Natural Scence, Lousana State Unversty, Baton Rouge, Lousana. MC:OC Moore Collecton at Occdental College, Los Angeles, : cal. MMNH Mnnesota Museum of Natural Hstory, Unversty of Mnnesota, Mnneapols, Mnn. ÎMT Musaum of_ Northern_ArzMa, _Flag8taff, Arzona. 182

196 183 MVZ rnsêm "ôr Vertëbr'âtë Zôôlôgÿ; Berkley, Cal. OU Museum of Zoology, Unversty of Oklahoma, Norman, Okla. PAC Academy of Natural Scences, Phladelpha, Pa. PM Peabody Museum, Salem, Mass. PMZ TU UMMZ Prnceton Museum of Zoology, Prnceton Unversty, Prnceton, N.J. Unversty of Texas (collecton), Austn, Texas. Unversty of Mchgan Museum of Zoology, Ann Arbor, Mchgan. USNÏv U. S. Natonal Museum (Smthsonan nsttute), Wash- : ngton, D. C. :YPM Yale Peabody Museum, Yale Unversty, New Haven, Conn.!

197 APPENDX Lst of Specmen Skns Examned; Localty Museum No, Age Sex Collector Kansas Comanche Co. KB st yr. Goss Oklahoma Blane Co. OU 2752 Adult C. D. Bunker Blane Co. OU 2792 C. D. Bunker Blane Co. OU 2881 Adult C. D. Bunker Blane Co. OU 2886 Adult C. D. Bunker! Blane Co. OU 2887 Adult C. D. Bunker Blane Co. OU 2895 Adult (f c. D. Bunker Blane Co. OU st yr. ct C. D. Bunker Blane Co. OU 2901 Adult C. D. Bunker Blane Co. OU 2902 Adult (f C. D. Bunker 1 Blane Co. OU 2905 Adult (T C. D. Bunker Blane Co. o u Adult ct C. D. Bunker Blane Co. USNM Adult (f C. D. Bunker j Blane Co. EU 20748? (f Maye Le onard 1 8 4

198 185 Localty Museum Number Age Sex Collector Blane Co. OU 2882 OU 289^? 9 C. D. Bunker C. D. Bunker Blane Co. OU 2904? 9 C. D.' Bunker Blane Co. USNM C. D. Bunker Caddo Co. OU 7l 5 Adult d G. M. Sutton Caddo Co. ou 5 Adult d G. M. Sutton Caddo Co. Adult d R. R. Graber 2846 Caddo Co. ou Juv. 9 R. R. Graber 2206 Caddo Co. Juv. 9 J. W. Graber 2286 Caddo Co. 1st W. 9 R. R. Graber Comanche Co. USNM 31^1271 1st Yr. d T. D. Burlej Comanche Co. UMVZ Adult d T. D. Burlej 6109 Dewey Co. ou st Yr. d G. M. Sutton Dewey Co. OU G. M. Sutton Murray Go. OU Adult d G. M. Sutton 7267 Murray Co. OU Adult d G. M. Sutton 7273 Murray Co. OU Adult d G. M. Sutton 7274 Murray Co. ou Adult d K. W. Haller 311 Murray Co. ou 9 G. M. Sutton 7268 Murray Co. ou 9 G. M. Sutton

199 1 8 6 p c a l î t y TOs eura" Fümbe r Age- lex -CcTl'leb^tOr P?exas Bexar Co. USNM st yr. c f H. P. Attwater Bexar Co. USNM Adult c f 1! Bexar Co. A M N H Adult ( f H. P. Attwater!Cooke Co. UfflZ G. H. Ragsdale Cooke Co. GMNH Adult ( f Comal Co. USNM Adult ( f W. H. Werner Edwards Co. USNM 18^835 1st W. 9 M. Cary Hays Co. TU Adult ( f R. R. Graber Kerr Co. A M N H Adult F. B. Armstrong 1 Kerr Co. AMNH Adult d " P. B. Armstrong Kerr Co. AMNH 1st yr. d P. B. Armstrong Kerr Co. MAM Adult d " P.. B. Armstrong !Kerr Co. 1 1 AMNH Adult P. B. Armstrong 2060 Kerr Co. AMNH Adult d P. B. Armstrong 2061 Kerr Co. AMNH 1st yr. d P. B. Armstrong 2062 Kerr Co. A M N H? d P. B. Armstrong 2063 Kerr Co. AMNH Adult d p. B. Armstrong Kerr Co. AMNH st yr. d A. P. Smth Kerr Co. AMNH Adult d A. P. Smth

200 Localty luseulq Number ' Age Sex. Collector.. Kerr Co, A M M Adult A. P. Smth Kerr Co. AlNH ? cf A. P. Smth Kerr Co. AMNH Adult cf Kerr Co. AMNH Adult c T A. P. Smth Kerr Co. A M M Adult A. P. Smth Kerr Co. AMNH Adult (f Kerr Co. AMNH Adult c T A. P. Smth Kerr Co. AMNH Adult 0 Kerr Co. AMNH Adult c T A. P. Smth Kerr Co. AMNH st yr. a A. P. Smth Kerr Co. AMNH st yr. ( f A. P. Smth Kerr Co. AMNH st yr. c? A. P. Smth Kerr Co. AWNH st yr. 2 A. P. Smth Kerr Co. AMNH ( f A. P. Smth Kerr Co. mm st yr. A. P. Smth Kerr Co. AMNH Adult A. P. Smth Kerr Co. AMNH A. P. Smth Kerr Co. AMNH st yr. A. P. Smth Kerr Co. AMNH Adult c T A. P. Smth Kerr Co. AMNH Adult A. P. Smth Kerr Co. AMNH st yr. d " A. P. Smth Kerr Co. AMNH st yr. d * A. P. Smth Kerr Co. AMNH st yr. c f A. P. Smth Kerr Co. AMNH Adult d " A. P. Smth Kerr Co. AMNH Adult ( f

201 188 Locarty rnseua'humb^h ' ^ g 0. ' Sex -'"Corrector ;Kerr Co. AvLNH st yr. cf Kerr Co. AMNH Adult ( f!kerr Co. A M M Adult cf Kerr Co. AMNH Adult Kerr Co. AMNH Adult c f :Kerr Co. AMNH Adult c f.kerr Co. AMNH Adult ( f Kerr Co, AMNH st yr. 0 Kerr Co. AMNH Adult c f Kerr Co. AMNH st yr. Ç Kerr Co. AMNH Adult 9 A. P. Smth Kerr Co. AMNH ? 9 A. P. Smth 1Kerr Co. AMNH Adult 9 A. P. Smth!!Kerr Co. AMNH st yr. 9 A. P. Smth 1Kerr Co, AMNH st yr. 9 A. P. Smth ;Kerr Co. UMMZ 1st yr. Kerr Co. T M 453 Adult c f D. W. Lay Kerr Co. TAM 454 1st yr. < f B. S. Ludeman Kerr Co. TAlM 455 Adult 9 B. E. Ludeman! Kerr Co. MVZ Adult c f C. S. Mueller j Kerr Co. MVZ Adult cf A. P. Smth! Kerr! Co. MVZ st yr. 9 A. P. Smth Kerr Co. USNM Adult c f A. P. Smth Kerr Co. USNM ? c f V. Baley! Kerr Co. H 8N M Adult c f V. Baley

202 LdcaTtÿ ' ; Kerr Co. Kerr Co. Kerr Co. Kerr Co. Kerr Co. Kerr Co. Kerr Co. Museum Mumtîer Age Sex Collector."" U S M l8^l 9 Adult (f M. Cary usm 181^150 Juv. M. Cary USNM Adult V. Baley USNM ? V. Baley USNM st yr. 9 V. Baley GMNH Adult d sadora Prnce^ CMNH Adult d sadora Prnce ; Kerr Co. CMNH d sadore Prnce Kerr Co. Kerr Co. Kerr Co. ;Kerr Co. Kerr Co.! Kerr Co. CMNH st yr. d sadora Prnce ; CMNH Adult d sadore Prnce ; CMNH Adult d P. B. Armstrong CMNH Adult d F. B. Armstrong CMNH st yr. d F. B. Armstrong CMNH st yr. d P. B. Armstrong Kerr Go. CMNH Adult d P. B. Armstrong j Kerr Co. Kerr Co. Kerr Co. CMNH st yr. d P. B. Armstrong CMNH Adult d P. B. Armstrong! CMNH st yr. d P. B. Armstrong Kerr Go. Kerr Co. GMNH st yr. d CMNH st yr. 9 sadora Prnce j 1! Kerr Co. Kerr Co. CMNH Adult? 9 P. B. Armstrong! CMNH st yr. 9 P. B. Armstrong jkerr Co. CMNH Adult 9 P. B. Armstrong Kerr Co. GMNH st yr. 7 9 P. B. Armstrong Kerr Co. CMNH Adult? 9 P. B. Armstrong

203 190 Localty Museum'FumFer Age".. Sex -Collect or... Kerr Co. CMNH Adult? 9 P. B. Armstrong Kerr Co. CMNH Adult? 9 Kerr Co. CMNH Adult 9 :Kmble Co. USNM Adult d T. D. Burlegh Knney Co. TU Adult d R. R. Graber :Medna Co. UMMZ Adult 9 A. J. Krn! 'Menard Co. AMNH Adult d A. P. Smth!Terrell Co. TU Juv.P.J * d W. A. Thornton ; Travs Co. AMNH 2063? d C. D. Oldrght ; Tom Green Co. USNM Adult d Lloyd 'Tom Green Co. USNM st yr. 9 w. Lloyd 1 Uvalde Co. TU Adult d R. R. Graber j Valverde Co. USNM st kv. d N. Lloyd Valverde Co. USNM Adult d W. Lloyd Valverde Co. USNM Adult d W. Lloyd 1 1 Valverde Co. USNM Adult d V. Baley 1Valverde Co. USNM Adult d H. C. Oberholsap Valverde Co. USNM Adult d M. Gary 1 Valverde Co. USNM st W. d M. Cary Valverde Co. 1 jvalverde Co. USNM ? d M. Cary USNM 6818 Adult d J. H. Clark %-Valverde Co. AMNH 1696 Adult d Mexco!Coahula MVZ 107+l l 1st yr. ^ H. H. Kmball

204 191 Locallty. Coahula ; Coahula! Coahula Coahula Coahula ; Coahula Coahula Coahula Coahula : Coahula Coahula ;Guerrero Jalsco Mexco. -- ' Museum Number Age Sex CoTTector ' ""j MVZ st yr. J A. H. Mller MVZ st yr. ct A. H. Mller MVZ ? 9 A. H. Mller 1 MVZ ? 9 A. H. Mller KÜ Adult J R. W. Dckerman KÜ st yr. R. W. Dckerman KÜ Adult J S. Anderson KU Adult e S. Anderson Adult J R. R. Graber Adult 9 R. R. Graber on Adult d" H. Land! MVZ W. W. Brown AMNH Adult J A. C. Butler USNM Adult J E.?/. Nelson Morelos! Nayart M N H J O T! D. W. Warner 1st W. J A. R. Phllps Nayart 1st W. Ç A. R. Phllps 2981 Nayart 1st W. A. R. Phllps 2997 Nayart Adult ^ A. R. Phllps 3009 Nayart Nayart Adult J A. R. Phllps st W. J' R. R. Graber ;Nayart 1st W. Ç R. R. Graber

205 192 EôcâlTy ' m s W m m m ï ë r ' ïge "Sex CôTector'. ; Snaloa JSNM $#0^6 1st W. $ A. J. Grayson Snaloa Adult ^ R. R. Graber Total Number of Specmens Examned 175 ' #Paratype

206 PHOTOGRAPHS

207 vo -pr- Flgure 1 Nestmates.. Larger cowblrd chck four days old, smaller cowblrd three days old, and black-capped vreo chck one-half day old (rght). Photo taken July, 1956, Comal County, Texas.

208 195 Fgure 2. Black-capped vreo nest ja stu» Photo taken July 1956, Caddo County, Oklahoma.