PARENTAL BEHAVIOR OF CACKLING CANADA GEESE DURING BROOD REARING: DIVISION OF LABOR WITHIN PAIRS

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1 The Condor92: Q The Cooper Omithoogka Society 1990 PARENTAL BEHAVIOR OF CACKLING CANADA GEESE DURING BROOD REARING: DIVISION OF LABOR WITHIN PAIRS JAMES S. SEDINGER~ AND DENNIS G. RAVELING Department of Widife and Fisheries Bioogy, University of Caifornia. Davis, CA Abstract. Behavior of pairs of Cacking Canada Geese (Branta canadensis minima) was studied on the Yukon-Kuskokwim Deta, Aaska, during the brood-rearing period in 1978 and Foraging time consisted of cyces of aert postures foowed by periods of grazing, when individuas searched for, or consumed, food. Femaes had shorter aert periods (X = 5.58 set) than maes (.z = 8.04 set) during a four possibe time periods (two time periods in each of 2 years), athough differences were significant in ony one of these periods. Femaes aso had significanty onger grazing periods than maes (X = set vs set) during three of the four time periods. Femaes spent an average of 74% and 58% of foraging periods actuay grazing prior to and during the mot, respectivey, whereas maes spent ony 52% and 58% of foraging time grazing during these two time periods. Less vigiance by femaes reative to maes resuted in femaes spending a greater percentage of their tota time budget grazing, athough the difference was significant ony before the mot in The proportion of foraging periods in which aduts were aert was positivey reated to the number ofgosings in their broods for both sexes, but when pairs associated with no gosings were removed from the anayses, the reationship was no onger significant for femaes. These data support the hypothesis that ong-term monogamy in geese is beneficia in part because maes are abe to assume greater responsibiity for vigiance after hatching, aowing femaes to repace depeted protein and ipid reserves. The reationship between aert behavior and brood size does not support a recent mode of parenta investment which predicts no such reationship (Lazarus and In&s 1986). Key words: Monogamy;parenta investment; behavior; Canada Goose; Branta canadensis minima. INTRODUCTION Geese form ong-term pair-bonds, and in most popuations pairs remain together throughout the year (Owen 1980), athough in the smaest geese pair members may frequenty be separated during fa migration and winter (Sedinger and Boinger 1987, Johnson and Raveing 1988). Maintenance of pair-bonds is thought to be beneficia for defense of winter food resources (Hanson 1953,Raveing 1970,BackandOwen 1989)and earier, and consequenty greater, spring weight gain by femaes (McLandress and Raveing 198 a). Advantages of this socia system accrue in part because femae geese rey heaviy on stored ipid and protein reserves to produce and incubate a cutch of eggs (Ankney and MacInnes 1978, Raveing 1979a), and femaes may require severa weeks in spring to acquire sufficient reserves Received 9 June Fina acceptance 19 September z Present address: Institute ofarctic Bioogy and Department of Bioogy and Widife, University of Aaska Fairbanks, Fairbanks, AK for both migration and breeding (Raveing 1979b, McLandress and Raveing 198 a, Ankney 1982). Presumaby, the presence of a mate during this period not ony pays a roe in stimuating hyperphagia in femaes (McLandress and Raveing b), but aso eevates their socia rank (Hanson 1953, Raveing 1970) thus providing better access to food resources and more time for feeding than they coud otherwise attain. Maintenance of famiy groups has aso been shown to eevate the socia status of juvenies (Hanson 1953, Fischer 1965, Raveing 1970, Back and Owen 1989), increasing their foraging time (Back and Owen 1984) and food avaiabiity (Back and Owen 1989). During nesting, defense of territories may be reated to femae foraging requirements (Ingis 1976). Protection of paternity (Mineau and Cooke 1979a, 1979b; Wesh 1988), reduced harassment of femaes (Ewaschuk and Boag 1972, Ingis 1977, Mineau and Cooke 1979b), or reduced predation (Adrich 1983) aso contribute to the advantages of pair-bond maintenance for one or both members of pairs. Because of the physioogica demands of egg 11741

2 BEHAVIOR OF CANADA GEESE DURING BROOD REARING 15 FIGURE 1. MALE-In I FEMALE_- u LJU UV-LIL I I 1 1 I / TIME (set) Typica pattern of grazing and aert periods for a pair of Cacking Geese. production and incubation, femae geese reach their owest annua eves of carcass protein and ipid when cutches hatch (Ankney and Mac- Innes 1978, Raveing 1979a). Protein eves are restored foowing hatching during a period when vegetation of high protein content is avaiabe (McLandress and Raveing 198 a, Cargi and Jefferies 1984, Sedinger and Raveing 1986). Of course ipids must aso be repenished prior to fa migration. Geese have precocia young and consequenty itte attention has been given to their parenta investment foowing hatching (but see Lazarus and Ingis 1978, Lesses 1987). Gosings are brooded reguary during their first 2 weeks (Ebbinge and Ebbinge-Dameijer 1975, pers. observ.), and both sexes may participate in vigiance for predators (Lazarus and Ingis 1978) and/ or aggressive interactions. Vigiance potentiay conficts with feeding time necessary for aduts, particuary femaes, to restore depeted protein and ipid reserves foowing hatching. To the extent that femae condition at the end of brood rearing infuences future surviva or reproduction, maes shoud adopt behaviors that aow their mates to restore depeted reserves because this ikey wi enhance their own fitness. We studied the behavior of adut Cacking Canada Geese (Branta canadensis minima) on the Yukon-Kuskokwim Deta, Aaska, during brood rearing in 1978 and Our goas were to describe the proportion of time aocated to important activities, examine the roes of both members of pairs in vigiance, and determine the reationship between brood size and vigiant behavior. We reported on gosing behavior esewhere (Sedinger and Raveing 1988). METHODS We observed adut Cacking Geese from an interconnected cabin and observation tower be- tween 27 June and 8 August 1978, and 20 June and 9 August The tower was ocated within a 40.4-ha study area 10 km south of Od Chevak (6 N, 165 W), a U.S. Fish and Widife Service fied station (see Mickeson 1975 for a genera description of the area). The peak of hatching occurred on 21 and 20 June in 1978 and 1979, respectivey, and fedging began during the first week of August (Sedinger and Raveing 1984). Observations used in our anayses were made between 06:OO and 23:O0. Foraging adut geese aternated reguary between aert periods and grazing periods when they searched for, or consumed, food (Fig. 1). These behaviors corresponded to head-up pus extreme head-up, and graze, respectivey, of Lazarus and Ingis (1978). We measured the duration of aert and grazing periods of maes and femaes whie foraging, to the nearest 0.5 sec. In a subsampe of these measurements, durations of both behaviors were measured for the same individua. The ratio of the average ength of grazing periods to the sum of the average engths of grazing pus aert periods provided an estimate, for each individua, of the percentage of foraging time spent grazing, i.e., searching for, or consuming, food. We assessed the independence of aert and grazing periods between members of pairs by examining the proportion of foraging periods that maes and femaes simutaneousy were aert (or grazing) compared to the proportiona overap in these behaviors expected by chance (i.e., the product of the proportions of time spent in a behavior by each member of a pair). If pairs coordinated their behaviors to minimize overap in time spent aert we shoud have observed ess overap in aert behavior than expected by chance. Individua pairs were observed for periods of 1 hr to 7 hr and the behavior of both members of the pair was assigned to one of the foowing

3 176 JAMES S. SEDINGER AND DENNIS G. RAVELING categories at 5-min intervas: foraging (which incuded grazing and aert behaviors), resting (sitting and not engaged in other activities), preening, bathing, moving (waking or running without engaging in other behavior), and agonistic activities. A singe estimate of activity for each observation period was cacuated as the percentage of S-min sampe points spent in each behavior during the period. We estimated the percentage of the tota time budget spent grazing by mutipying the percentage of time spent foraging (from 5-min sampes) by the proportion of tota foraging time actuay spent grazing by individuas for whom the engths of aert and grazing periods were measured. Time spent aert was estimated as the product of foraging time and the proportion of foraging time spent in aert postures. Each of these sampes (activity over an entire observation period) was treated as an independent estimate of behavior, athough geese were unmarked and there was some potentia for samping some pairs more than once during a summer. We cacuated approximate probabiities of repeatedy samping pairs by counting a pairs within 400 m of the observation tower neary daiy in 1978 and The peak number present during a singe count was used to cacuate the probabiity of seecting a pair for observation in each year. We assumed that each pair was equay ikey to be seected for an observation period and used the binomia distribution to estimate the probabiity of a pair being samped more than once. We distinguished maes from femaes based on the arger body sizes of maes (Raveing 1978) and recorded size of broods for a pairs samped. For anaysis of behaviora data we divided the brood-rearing period into two parts: (1) prior to the mot of adut remiges (premot, first 23 days after hatching), (2) adut mot pus the gosing fedging period (mot-fedge, 24th-49th days after hatching) because adut behavior might depend on mot status either for nutritiona (Raveing 1979a, Ankney 1984) or predator avoidance reasons. This criterion aso divided the brood-rearing period at about its midpoint. The two time periods were separated by 15 and 14 Juy in 1978 and 1979, respectivey. Our estimates of the percentage of the tota time budget spent grazing and aert were products of independent estimates of time spent foraging and the proportion of foraging time spent grazing or aert. We cacuated the variance of our estimates of percentage of time spent grazing and aert from the formua for the variance of the product of two random variabes (Mood et a. 1974, p. 180). Between-year and between-sex comparisons of percentage of time spent grazing and aert were made using t-tests because of the composite nature of the estimates. Other between-sex or between-time-period comparisons of percentage of time spent performing behaviors were made using Mann-Whitney U-tests. Comparisons between the sexes of percentages of foraging periods spent grazing were made using Mann-Whitney U-tests. We tested for diurna variation in percentage of time spent in each of the behaviora categories using Kruska-Wais tests, with 2-hr time periods between 06:OO and 22:00 serving as treatment eves. Individuas were repeatedy samped to estimate the engths of aert periods and feeding bouts. Therefore, some measures of these behaviors were not independent with respect to individuas. We anayzed between-sex differences in the duration of these periods using a nested ANOVA, with individuas as the nesting factor, to account for the ack of independence of sampes coected from the same individua. The reationships between brood size and percentage of time spent foraging or percentage of foraging time spent aert were examined for both maes and femaes by inear regression. For anaysis of the percentage of foraging time spent aert vs. brood size reationship, sampes were combined across years and time periods (premot, mot-fedge) after first testing for variation in adjusted mean eves of percentage of foraging time spent aert in each time period using ANCOVA. Anaysis of covariance and nested ANOVA were performed using the BMDP Statistica Computing Package (Dixon 1985). RESULTS As many as 100 broods were within 1 km of the observation tower in 1978 which provided a maximum estimate of the number of broods from which behaviors were samped. The peak numbers of broods counted on the 40.4-ha study in 1978 and 1979 were 46 and 24, respectivey, which provided a minima estimate of the number of broods samped. For 46 broods samped 49 times (sampe size for time budgets in 1978) the binomia probabiity of samping any one brood more than once was if broods dis-

4 BEHAVIOR OF CANADA GEESE DURING BROOD REARING 177 TABLE 1. and Lengths (set) of grazing and aert periods (X -t SE) of adut Cacking Geese with broods during 1978 Premot Mot-fedge Grazing Aert Grazing Aert Sex Maes & 0.45 * 1.95 & 1.10 * 0.37 * 0.47? 1.09? 1.52 (1OP (150) (107) (63) (246) (219) (184) (95) **b * ns * * ns ns ns Femaes ? 0.87? 0.84 & 0.48 f 0.48 * (134) (128) (109) (67) (222) (177) (177) (98) a Number of feeding bouts or aert periods measured. b Statistica comparison (nested ANOVA, see Methods) of maes and femaes; **, P < 0.001; *, P < 0.05; ns, not significant. tributed themseves randomy. The comparabe probabiity for 1979 was Therefore it is ikey that we did sampe some broods more than once. Even under the conservative assumption that ony 24 broods were avaiabe for samping, the probabiity that we samped five broods more than once is 0.11 (0.6465). We beieve these estimates are conservative because our peak counts underestimated the number of broods actuay avaiabe for samping over the course of a fied season. It is therefore unikey that our assumptions about sampe size infated the sensitivity of our statistica anayses sufficienty to have atered our hypothesis tests. We detected significant diurna variation in behavior in ony two (bathing and resting of maes in 1979) of 24 tests (six behaviora categories for two sexes in each of 2 years). Because of the sma number of significant resuts, given the arge number of statistica tests, and the absence of a discernibe pattern, we attributed to samping error the observed diurna variation for two be- haviors in 1979 maes. We therefore performed subsequent anayses on behaviora data pooed across daiy time periods. Whie foraging, femaes had significanty onger grazing periods than maes prior to the mot in both 1978 and 1979 and during the motfedge period in 1978 (Tabe 1). In contrast, maes had onger aert periods than femaes both prior to and during the mot in both years, athough the difference was significant ony during the 1979 premot period. Differences in the duration of grazing and aert periods resuted in femaes searching for, or consuming, food a arger percentage of foraging periods than did maes during a four of the possibe time periods, highy significanty so prior to the mot in both years (Tabe 2). We detected no systematic coordination of aert periods by pairs; 17 of 3 3 pairs for which we simutaneousy observed behavior for the mae and femae overapped in aert behavior ess than expected by chance, whie the remainder overapped more than expected. TABLE 2. Mean percentage (kse) of foraging periods actuay spent grazing (searching for or consuming food) by adut Cacking Geese on the Yukon-Kuskokwim Deta. Sex 1978 Premot Mot-fedge 1979 Maes Femaes 50.9 & 4.7 ( ) (17)b P = ( ) (15) 54.0 * 4.4 (30.~-djo.7) P < ( ) (17) * Range of observed vaues. b Number of separate intervas in which % of time spent grazing and aert were determined. C Statistica comparisons of maes and femaes were made with Mann-Whitney U-tests ? 4.6 ( ) ( ) (26) (26) P = 0.09 P < f ( ) ( ) (25) (28)

5 178 JAMES S. SEDINGER AND DENNIS G. RAVELING TABLE 3. Time budgets of adut Cacking Geese during brood rearing. Time period Mean (SE) percentage of time devoted to behaviors (W Grazing Aert Resting Preening Bathing Moving Agonistic 1978 Premot (25) Maes b 31.2 k * ? * Femaes 41.4 * * k ? t Mot-fedge (24) Maes ? f f 0.1 Femaes 46.1? ?Z Premot (23) Maes k ? f t ? 0.3 Femaes 43.4?= ? f ? Mot-fedge (29) Maes 35.5 * * Femaes & * S Both members of pain were samped simutaneousy so sampe size represents both maes and femaes. b SE for grazing and aert was estimated as the ratio of the SD (estimated from Mood et a. 1974, see Methods) and the square nmt of the minimum sampe size of estimates used in the cacuation. Grazing was the dominant behavior of femaes, whie maes spent simiar amounts oftime grazing and aert, before the mot in both years of the study (Tabe 3). There was no betweenyear difference in percentage of time devoted to grazing by either sex prior to the mot (P > 0.10, both sexes), but femaes spent a greater percentage of time grazing during this period than maes (significant in 1979, P < 0.05). Maes were aert significanty more ofthe time than femaes before the mot (P < 0.005, both years). We detected no significant variation in aert or grazing time between the premot and mot-fedge periods for either sex (P > 0.05, a comparisons). Nevertheess, shifts in behavior by both sexes between premot and mot-fedge eiminated differences between the sexes in time devoted to aert or grazing during mot-fedge (P > 0.05, both behaviors). Femaes rested a greater (but not significanty so, P > 0.18) percentage of the time than maes prior to the mot (average from both years 30% for femaes vs. 23% for maes). Maes were invoved in aggressive interactions a greater percentage of time than femaes (P < 0.03, both years), but there were no other significant between-year or between-sex differences in behavior before the mot. During the mot-fedge period, femaes reduced the time devoted to resting from that of the premot period in both years but the difference was significant ony in 1978 (P < in 1978, P > 0.2 in 1979) (Tabe 3). Maes reduced their resting time in 1978 (P < 0.02) but not in 1979 (P > 0.68). Time invoved in aggressive encounters by maes aso decined between the premot and mot-fedge periods during 1978 (P < 0.005) and 1979 but the difference was not significant in the atter year (P > 0.1). As a resut of differentia changes in behavior by maes and femaes between the premot and mot-fedge periods there were no significant differences in the time budgets of the two sexes during the motfedge period (P > 0.30, a behaviors). The percentage of foraging periods spent in the aert posture was significanty reated to brood size for maes (P < ) and femaes (P < 0.05, Fig. 2). The reationship was not significant for femaes when broods of zero were excuded from the anayses (P > 0.50) but remained so for maes (P < 0.05). DISCUSSION ADULT VIGILANCE, DIVISION OF LABOR AND FEMALE BODY CONDITION Gosings of arctic nesting geese suffer high rates of predation foowing hatching, particuary during their first 2 weeks of ife (e.g., MacInnes et a. 1974, Mickeson 1975). Parenta protection is important in reducing predation, and we have observed increased vunerabiity to predation for gosings separated from their parents. Parenta behavior by Cacking Geese reduces predation either by direct defense of the brood (primariy against Parasitic Jaegers, Stercorarius parasiticus, and Gaucous Gus, Lams hyperboreus) or

6 by eading the brood to a safe environment, which is the principa response to arctic foxes (Aopex ugopus). Vigiance by the aduts presumaby increases the effectiveness of their defense of the brood. Martin et a. (1985) reported a significanty ower recapture rate for web-tagged gosings of widowed femae Lesser Snow Geese (Chen. c. caeruescens) than for gosings of pairs, suggesting that one femaes compared to intact pairs were either ess vigiant or ess capabe of defending their broods, or both. Femaes might compensate for the oss of a mate during brood rearing by increasing their own vigiance as do incubating Lesser Snow Geese (Martin et a. 1985). However, this woud reduce the femaes feeding time and possiby, therefore, the restoration of their protein and ipid reserves before autumn migration. Maes may directy contribute to gosing surviva or growth by maintaining brood integrity or by excuding other broods from the immediate foraging area (pers. observ.), in addition to their roe in predator detection and defense. The investment in aert behavior by maes is associated with their oss of carcass protein and body mass foowing hatching (Raveing 1979a). Mae investment in vigiance aows femaes to spend more time grazing, thus restoring depeted protein and ipid reserves. We beieve that adut maes woud gain itte by abandoning broods because maes undergo smaer fuctuations in carcass protein content than do femaes (Raveing 1979a) and, therefore, have ess need than femaes to consume arge amounts of protein between hatching and fedging. Maes that abandoned their mates and broods and attempted to form new pair-bonds the next winter woud risk reduced reproductive success (Cooke et a. 1981). BEHAVIOR OF CANADA GEESE DURING BROOD REARING 179 t$ G e g I- IOOr MALES y= x 80 r2= 0.37 P<O.OO I n=39 t 601 e 8o 60t F FEMALES y= X r2=0.12 p<o 05 n=3; / /e.8 : o! NUMBER OF GOSLINGS FIGURE 2. Reationship between percentage of foraging periods spent aert and brood size. Regression equations incude data from pairs with no gosings. e PARENTAL INVESTMENT Lazarus and Ingis (1986) proposed for species with precocia young that when parenta investment is unshared among brood members there shoud be no reationship between investment and brood size. In Lazarus and Ingis terminoogy, vigiance by aduts is an unshared investment because benefits experienced by one gosing do not diminish benefits experienced by sibings and they predicted there shoud be no reationship between investment in this behavior and brood size. Lazarus and Ingis (1978) and Lesses (1987) did not detect a reationship between adut behavior and brood size in Pink-footed Geese (Anser brachyrhynchus) and Lesser Snow Geese, respectivey. In contrast, Schinder and Lamprecht (1987) observed severa positive correations between aert and aggressive behaviors and brood size, and negative correations between foraging time and brood size in semicaptive Bar-headed Geese (Anser indicus). Body masses of adut femae Canada Geese when their gosings fedged were negativey correated with brood size (Lesses 1985). Our observation that adut vigiance increased with brood size is consistent with those

7 180 JAMES S. SEDINGER AND DENNIS G. RAVELING of Schinder and Lamprecht (1987) and Lesses (1985), and these studies are inconsistent with the hypothesis of Lazarus and Ingis (1986). ACKNOWLEDGMENTS Carence Rhode Nationa Widife Range (now Yukon Deta Nationa Widife Refuge) provided equipment and ogistica support. C. P. Dau suggested the use of the study area, without which this study woud have been difficut. The Coeae of Agricuture. Universitv of Caifornia, Davis, proqided financia support. E. d Coach, F. Cooke, and M. R. McLandress provided hepfu comments on an earier draft. We especiay thank C. M. Sedinger for assistance with the coection of data. LITERATURE CITED ALDRICH, T. W Behavior and energetics of nesting Canada Geese. M.Sc.thesis. Univ. of Caifornia, Davis. ANKNEY, C. D Annua cyce of body weight in Lesser Snow Geese. Wid. Sot. Bu. 10: ANKNEY, C. D Nutrient reserve dynamics of breeding and moting Brant. Auk 101: ANKNEY, C. D., AND C. D. MACINNES Nutrient reserves and reproductive performance of femae Lesser Snow Geese. Auk BLACK, J. M., AND M. OWEN Importance of the famiy unit to Barnace Goose Brunta eucopsis offspring-a progress report. Nor. Poarinst. Skr. 181:79-g% BLACK, J. M., AND M. OWEN Agonistic be- ter: effects ofbody size and food resources on goose socia organization, p In M. Weer [ed.], Waterfow in winter symposium. Univ. Minnesota Press, Minneapois. LAZARUS, J., AND I. R. INGLIS The breeding behaviour of the Pink-footed Goose: parenta care and vigiant behaviour during the fedging period. Behaviour 65: LAZARUS, J., AND I. R. INGLIS Shared and unshared parenta investment, parent-offspring confict and brood size. Anim. Behav. 34: LESSELLS, C. M Brood size in Canada Geese: a manipuation experiment. J. Anim. Eco. 55: LESSELLS, C. M Parenta investment, brood size and time budgets: behaviour of Lesser Snow Goose Amer. c. cueruescens famiies. Ardea 75: MACINNES, C. D., R. A. DAVIES, R. H. JONES, B. C. LIEFF, AND A. J. PAKUL.AK Reproductive efficiency of McConne River sma Canada Geese. J. Wid. Manage. 38: MARTIN, K., F. G. COOCH, R. F. ROCKWELL, AND F. COOKE Reproductive performance in Lesser Snow Geese: are two parents essentia? Behav. Eco. Sociobio. 17~ MCLANDRESS, M. R., AND D. G. RAVELING. 198 a. Changes in diet and body composition of Canada Geese before svrinn m&ration. Auk 98~ MCLANDRESS, M. R.,.&D D. G. RAVELING. 198 b. Hyperphagia and socia behavior of Canada Geese prior to spring migration. Wison Bu. 93: MICKELSON, P. G Breeding bioogy of Cacking haviour in Barnace Goose focks: assessment, investment and reproductive success. Anim. Behav. 37: CARGILL, S. M., AND R. L. JEFFERIES The effects of grazing by Lesser Snow Geese on the vegetation of a sub-arctic sat marsh. J. App. Eco. 21: Geese and associated species on the Yukon-Kuskokwim Deta, Aaska. Wid. Monogr. 45. M~NEAU, P., AND F. COOKE. 1979a. Territoriaity in Snow Geese or the protection of parenthood- Ryder s and Ingis hypotheses reassessed. Widfow 30: MINEAU, P., AND F. COOKE. 1979b. Rape in the Lesser COOKE, F., M. A. BOUSF~ELD, AND A. SADURA Snow Goose. Behaviour 70: Mate change and reproductive success in the Lesser Snow Goose. Condor 83: DIXON. W. J BMDP statistica software. Univ. MOOD. A. M.. F. A. GRAYBILL. AND D. C. BOES Introduction to the theory of statistics. 3rd ed. McGraw-Hi, New York. Caifornia Press, Berkeey. OWEN, M Wid geese of the word. Batsford, EBBINGE, B., AND D. EBBINGE-DALLMEJJER Barnace Geese (Brunta eucopsis) in the Arctic summer. Nor. Poarinst. Arbok: EWASCHUK, E., AND D. A. BOAG Factors affecting hatching success of densey nesting Canada Geese. J. Wid. Manage. 36: London. RAVELING, D. G Dominance reationships and agonistic behavior of Canada Geese in winter. Behaviour 37: RAVELING, D. G Morphoogy of the Cacking Canada Goose. J. Wid. Manage. 42: FISCHER, H Das Triumphgeschrei der Grau- RAVELING, D. G. 1979a. The annua cyce of body gans (Anser unser). Z. Tierpsycho. 22~ HANSON, H. C Inter-famiy dominance in Cancomposition of Canada Geese with specia reference to contro of reproduction. Auk 96: ada Geese. Auk 70: _ RAVELING, D. G The annua energy cyce of INGLIS, I. R Agonistic behaviour of breeding the Cacking Canada Goose, p In R. L. Pink-footed Geese with reference to Ryder s hy- Jarvis and J. C. Bartonek [eds.], Management and pothesis. Widfow 27: bioogy of Pacific Fyway geese. OSU Book Stores, INGLIS, I. R The breeding behaviour of the Corvais. Pink-footed Goose: behavioura correates ofnest- SCHINDLER, M., AND J. LAMPRECHT Increase ing success. Anim. Behav. 25~ of parenta effort with brood size in a nidifigous JOHNSON, J. C., AND D. G. RAVELING Weak bird. Auk 104: famiy associations in Cacking Geese during win- SEDINGER, J. S., ANDK. S. BOLLINGER Autumn

8 BEHAVIOR OF CANADA GEESE DURING BROOD REARING 181 staging of Cacking Canada Geese on the Aaska SEDINGER, J. S., AND D. G. RAVELING Foraging Peninsua. Widfow 38: behavior of Cacking Canada Goose gosings: im- SEDINGER, J. S., AND D. G. RAVELING Dietary pications for the roes of food avaiabiity and seectivity in reation to avaiabiity and quaity processing rate. Oecoogia 75: of food for gosings of Cacking Geese. Auk 101: WELSH, D The reationship of nesting density to behavior and reproductive success of Back SEDINGER, J. S., AND D. G. RAVELING Timing Brant. M.Sc.thesis. Univ. Idaho, Moscow. of nesting by Canada Geese in reation to the phenoogy and avaiabiity of their food pants. J. Anim. Eco. 55: