1957 WILLIAMSON, Post-Nuptial Molt in the Wheatear [129

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1 Vl. XXVIII 1957 WILLIAMSON, Pst-Nuptial Mlt in the Wheatear [129 THE ANNUAL POST-NUPTIAL MOLT IN THE WHEATEAR (Oenanthe enanthe) BY KENNETH WILLIAMSON In thse migratry passerines which underg a cmplete pst-nuptial mlt the change prceeds wi h greater rapidity than in sedentary species, an adaptatin t the need t assume a full set f remiges and rectrices in time fr the fall migratin. Tlhe Wheatear (Oenanthe enanthe) affrds an excellent example. It is a cmmn summer visitr t Fair Isle, where it is single-brded between the middle f May and early J,uly, thugh a few late pairs may still,be attending yung at the beginning f August. The yung f the year, which mlt nly the juvenal cntur-feathers and median cverts (smetimes als a few lesser and inner majr cverts) when frm 5-8 weeks ld, leave frm the middle f August, the adult bir,ds fllwing at the end f the mnth and in early September. The first week f September is the peak-perid fr.passage f larger birds which have nested in Greenland and Iceland, Oenanthe e. leucrrha and schi leri. The data n which this nte is,based have been cllecte during labratry examin,atin f lcal birds trapped at Fair Isle Bird Observatry ver l he past 8 years, and incrprate bservatins n sme 80 individuals, a few f which have been captured n mre than ne ccasin during the perid f the tk. The mlt cmmences abut,he time the yun,g leave the nest, during the last week f June, and befre they achieve independence f their parents in the secnd week f July. Sme birds have already finished by mid-august. A ½ "A " which had just started n June 29, 1956 had t all intents and purpses finished by August 17, t,he ninth primary and innermst secndaries being a little shrt f their full lengt h. The perid ccupied by the change i,s therefre f the rder f 7-8 weeks. The sequence f the mlt is the same as in ther ten-primaried scines studi'ed at Fair Isle -ø,.b,eginn.ing with the innermst primary and its cvert, the change prceeding utwards 3. The terriaries (which Witherby et al. (1941) call the "lng innermst secndaries," but which mlt as a distinct grup and shuld be separately identified) and the mid-wing.cverts are the next in turn. Here the utermst greater r majr cverts are a little ahead f the in, ner nes as a rule; they are succeeded by the lesser r minr cverts, and finally the median grup. The rep}acement f each primary cvert is linked with that f the crrespnding remex. In many the under wing-cverts are still in sheath when the uppers have finished and the wing-mlt is :far advanced. When the replacement f primaries is well under way, mlt f the secndaries begins--als in mid-wing, the successin being inwards twards t, he renewed tertiaries. The bastard-win.g (alula) and shrt tenth primary are replaced during the grwth f the ninth primary, Fair Isle is at Latitude 59 32' N., Lngitude 1 37' W., ff nrthern Sctland midway between the island-grups f Orkney and Shetland.

130J Bird-Banding WILLIAMSON, Pst-Nuptial Mlt in the Wheatea,r july and khese are nrmally cmplete befre the innermst secndaries are fully extended.

2 130J Bird-Banding WILLIAMSON, Pst-Nuptial Mlt in the Wheatea,r july and khese are nrmally cmplete befre the innermst secndaries are fully extended. The tail-mlt cmmences early, tgether,with upper and under tail-cverts, shrtly after the innermst primaries have begun. Cmpletin f the tailmlt ccupies 3-4 weeks: a 9 withut any tail n Jul'y 25, but with the new feal hers in pin, had a full tail by August 17; and a d with the tail in pin n August 6 had it very nearly c mplete {51 min.) n August 28. Bdy mlt als begins early, usually with the sides f breast and rump, clse}y fllwed by scapulars, mantle, flanks, the remainder f the under-parts and head. In the Star}ing, which is nn-migratry in the Shetland regin lthugh sme lcal mvement ccurs), it seems t be t'he rule fr the remiges t grw singly, s that ne is fairly well develped befre the next in successin leaves its sheath. In the Wheatear it is custmary fr the primaries t be renewed tw r even three tgether, especially in the early stages, s that the whle prcess is greatly accelerated, and is cmplete in half the time. A lst-summer 8 f July 8 had already renewed pri,maries 1-4, the fifth was prtm,ding frm its sheath and the ld sixth had been shed; a 9 n July 9.had the five innermst primaries grwing; and a lst-summer f the same date had the fur innermst in the left wing and the five innermst in the right vin,g all partly extended. The birds f July 8 and 9 and a number f thers at a simi}ar stage had the 'whle tail in pin, nne f the ld feathers remaining--examples can be fund n reference t Tables I and II. Naturally, such severe,mlt interferes with the birds' capacity fr sustained flight, and dubtless renders them mre liable t predatin. Indeed, ne is aware f but little activity n the part f adults at t.his cri.tical.perid, and the fact l hat mre are caught in the traps sited alng the dry-stne walls at this time than earlier in the summer suggests that they keep very much t cver and are less sprightly in avidmg capture. The histry f 9 "A62.580," wh was recaptured 9 times between June 29 and Au, gust 17, always in the same trap, shws that adults remain n their territries during the perid,f the mlt. Other adults, d and 9, have,been taken twice r thrice ver,nuch the same perid under similar circumstances. It wuld be reasnable t su,ppse that a rapid physilgical prcess f this nature puts a severe strain n the bird, particularly as it must restrict the nrmal feeding rutine t sme extent. Yet there is little evidence f the marked decrease in weight which ne might expect t ac.cmpany t,his prcess, especially during the early perid f heavy mlt. Such data as we have been able t gather suggest the prbability f a gain n "nrmal" weight befre the nset f mlt, maintained durin,g this first exacting frtnight,,with a slight fall later. Repeat weighings f varius individuals gives these results. A d at 25.7 gin. when in mlt n July 19 was 2 gin. heavier than in the evening f May 26, a time f day when ptimum weight is attained; and a 9 Starling (Sturnus vulgaris), Meadw Pipit (Anthus pratensis), Rck Pipit (A. spinletta), Twite (Carduelis fiavirstrisj and Huse Sparrw (Passer dmesticus). athe American ntatin, in which the first primary is the innermst and the tenth (if present) is the minute uter feather, is therefre the mre lgical. and it is adhered t in the present paper.

3 Vl. XXVIII 1957 WILLIAMSO'-, Pst-N,,ptia! _Il]t in the hecttear [131 at 24.6 gin. in the early mrning f July 25 was 2 gm. better than in mid-afternn f May 29. Anther, nly 22.8 gm. in nid-mrni, g f June 4 was 2.6 gm. heavier when in mlt at 0415 hrs. n July 13. Less cnclusive is a 9 whse early mrning weight f 24.8 gm. n July 16 was a fractin (0.3 gin.) belw a mid-day figure fr April 28-- thugh if due allwance is made fr diurnal variatin, this nay well represent a real gain. Her mid-lnrning weight n A,u gust 24, with the nlt ver, was 25.3 gin. The nly lng series f weighings is fr 9 "A62.580," wh was 30 gm. (a high value fr a Fair Isle Wheatear) in nid-mrning f June 30 wivh the change just begun; 29.6 gin. and 28.8 gm. in nid-afternn f July 14 and 15 respectivel. y; 26.9 gm. in the early mrning.f July 25; and 26.7 gin. in mid-mrning f August 17 with the nlt virtually ver. A 5 shwed a similar fall frm 27.1 gin. n July 11 t 24.5 gm. n August 23. bth weighings late in the day. This same bird had shwn virtually n change between July 2 and August 3 in the previus year, In additin t lsing the whl.e tail and several remiges at nce early in the prceedings. it appears t be fairly general in the Wheatear fr at least the three innermst secndaries (and smetimes all these feathers) t be drpped at a later stage. Thus, a n August 3 had a new first secndary and the remaining five partly extended r in pin, while anther n this date was withut a single secndary in either wing. This cnditin ccasinally leads t an irregular sequence in the develpment f the new feathers. Mst f the recrds available fr the third week f July shw cmpletin f the grwth f primaries 1-5, fllwing which the birds' incapacity fr sustained flight may be less, since it appears t be usual fr the remaining fur functinal primaries t grw in pairs, s that the sixth and seventh are ab'ut hal. f-grwn when the eight and ninth emerge frm t.heir sheaths. A curius fact is that at this stage the wing-length increases nticea,bly. This is due presuma,bly t the lsening f the ld eighth and ninvh primaries befre they finally drp away. Our "A62.580," starting mlt with a win.g f 100 mm. at the end f June, gradually increased t 103 mm. n July 20, when the inner primaries were fully grwn. At the next examinatin n Jul'y 23 the d distal remiges had fallen ut and the wing-length, 86 nm.. was that f the fifth primary. When taken again 25 days later, with the eighth primary fully grwn, the wing-length was again 100 m n. In tw days, July 23-25, the seventh primary increased its len gth by 9 mm. and the lnger sixth by nly 6 min., suggesting that grwth may be mst rapid just after prtrusin frm the sheath. During the 9 days August ; "JB 582" extended the ninth primary frm the sheath t half its lengt. h and the eighth t abut three-quarters, whilst the secnd,and third secndaries practically cmpleted their grwth. Mlt f the tail is ften irregular. smetimes the utermst and smetimes the middle pair taking precedence; nce, n August 7, we have "uters half-grwn, penultimate pair three-quarters, the rest new": and nce, n August 4, "uters and 2 middle eathers ld, rest missing." Mlt f the remiges is very rarely asynchrnus, b.ut there is a f

4 ]Sird-]5 nding J32] WILLIAMSON, Pst-Nuptial Mlt in the Fheatear July,-. c 0 0 N -- 0 O0 0 N,, O N 0 OOOOOO0 ONNO N OOOOOOOOOO0 'O NO O c ' ' ' '

5 ¾l XXVIII WILLIAMSON, Pst-Nuptial Mlt in the Wheatear [133 moo OONO

WILLIAMSON, Pst-N.ptial Mlt in the Wheatear July :Bird- Banding July 16 with primaries 1-5 in sheath in the right wing, and with 4-5 nly in pin, 3 half-grwn, and 1-2 practically finished in the right.

6 WILLIAMSON, Pst-N.ptial Mlt in the Wheatear July :Bird- Banding July 16 with primaries 1-5 in sheath in the right wing, and with 4-5 nly in pin, 3 half-grwn, and 1-2 practically finished in the right. The mst strikin, g instance was a lst-summer?, n May 18 with primaries 6-7, all secndaries and the third greater cvert new in the left wing and the inner greater cverts missing frm the right, and median and lesser cverts new in bth wings. This is the nl'y instance f irregular spring mlt in ver 300 birds examined. I have n nte f the shrt tenth primary and alula in mlt prir t August 1; being a minute feather, the tenth primary is nearly always cmplete befre the ninth, and this and the alula have ften finished ;vhen secndaries 5-7 are still half-grwn. A?, with the enth primary in pin n August 1 had this feather fully extended n August 4; the bastard-wing, partly extended n the first ccasin, was by then cmplete. Frm August 17 and 18 we have ccasinally trapped adults in which the change was cmplete, and mst have finished by the end f the mnth. The very late recrds are almst certainly individuals which, thrugh lss f an early clu,tch, have nested a secnd time. A which up t a week previusly had attended flying yung in the vicinity f ne f the traps was caught n August 23 with the ld primaries 7-10 remaining, the sixth in pin, and 1-5 n.t mre than half-grwn, a stage mst birds have passed a mnth befre. The tail was little mre than half.grwn. One f the juveniles f this family, captured n August 29, had the,bdy-mlt nly just beg un n mantl, e, scapulars, sides f breast and flanks. By that date mst f the year's birds have left the isle. Occasinally birds n passage frm farther nrth-west (Faere Islands, Iceland, Greenland) shw signs f uncmpleted mlt, but this is nrmally cnfined t the ninth primary and innermst secndaries being a few millimeters shrt f their full length. A final cmment might be made n the severity f the mlt in its early stages. It is highly imprbable that birds in the cnditin descri.bed fr early July culd find an adequate supply f fd fr themselves and several nestlings r nn-independent juveniles (which are attended fr abut 10 days after leaving the nest. ; and, as suggested abve, it is prbable that the nset is deferred until breeding is at an end. Nevertheless, the,bird must have 7 r 8 clear weeks in which t prepare fr the fall migratin. The severity f wing and tail. mlt, cmbined with the lateness f the breeding seasn at Fair Isle and farther nrth, restricts the Wheatear t a single brd. Witherby et al. (1941) state that the species is d.u,ble-.brded in Shetland as in parts f England, but the Venables (1955) and ur wn bservatins ver the past 6 years shw that this is nt s. Furthermre, Witherby gives "dublebrded" fr the Greenland race leucrrha, and Salmnsen (1951) qutes Fencker t the effect that a secnd brd can prbably be reared in very mild years under ideal cnditins. Nichlsn (1930) in Greenland and Wynne-Edwards (1952) in Baffin Island have als sugsested that leucrrha can be duble-brded. That any can breed twice, successfully, in the ne seasn seems t me an exceedingly remte pssibility; and there is nthing in the cases these authrs give f presumed first,brd juveniles assisting t feed "secnd-brd" nestlings which is incnsistent with the mre likely alternative that independent juveniles, attracted ut f curisity, were taking a spradic part in

7 Vl. XXVIII 1957 LASKEY, Tu/ted Titmuse Li/e Histry [135 "helping" a late-nesting pair. Ni,chlsn's paper lays stress n their inquisitiveness, and at Fair Isle we have watched yung Wheatears shwing keen interest in a nestful f Twites; the fact that in his case the "helpers" were in different stages f mlt t first-winter plumage, and thus almst certainly f different ages, supprts this alternative. SUMMARY The prgress f the cmplete pst-nuptial mlt in the Wheatear (Oenanthe enanthe) is described frm examinatin f ver 80 specimens trapped at Fair Isle Bird Observatry. Mlt cmmences in late June, unless delayed by late nesting, and ccupies 7-8 weeks, finishing in the third week f August. Juveniles mlt the cntur feathers, median and ccasinally sme greater and lesser cverts when between 5-8 weeks ld. Wing and tail mlt are very severe in the early stages, and the birds inactive. The few weight recrds frm "repeat" trapping suggest a gain n nrmal weight at the nset and a slight lss twards the end f the perid. The severity f wing and tail mlt restricts the Wheatear t a single brd at Fair Isle and farther nrth (Faere Islands, Iceland. Greenland). REFERENCES NICHOLSON, E. M Field-ntes n Greenland Birds. Ibis (19301: SaLO aons ;N, F Grinlands Fugle. (The birds f Greenland.) Vl. 3. Cpenhagen. V ;NaBLZS, L. S. V. and U. M Birds and.mammals f Shetland. Edinburgh. WITHERBY, H. F. et al The handbk,f 'British birds. Vl. 2. Lndn. WYNNE-EDWARDS, V. C Zl,gy f the Baird expeditin ( The birds bserved in central and sutheast Baffin Island. Auk, 69: India St., Edinburgh, Sctland. SOME TUFTED TITMOUSE LIFE HISTORY BY AMELIA Pt. LASKEY The Tufted Titmuse (Parus biclr) is a cmmn permanent resident in Tennessee, particularly in wded areas. They are regular visitrs at feeding statins in many residence sectins f Nashville frm early autumn until spring if sunflwer seeds, nutmeats, peanut butter r suet are pr.vialed. Mst f them g t the,wds in spring t nest. They ften return t my hme banding statin in May, June r July, bringing their nearly mature fledglings. AGE Frm 1931 t 1956, I have.banding recrds fr 327 individuals at lny hme and substatins in the suth-western sectin f Nashville. As this species enters banding traps rather freely, it is pssi'ble t gather

The Effect of Various Types of Brooding on Growth and Feed Consumption of Chickens During the First 18 Days After Hatch

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