886 ShortCommunications [Auk, Vol. 101

DUNN,E.H. 1975. Caloricintake of nestingDouble- PRINCE, P. A., C. RICKETTS, & G. THOMAS. 1981. crested Cormorants. Auk 92: 553-565. Weight lossin incubatingalbatrosses and its im- GROSCOLAS,R., Y. LE MAHO, H. BARRE,& B. DESPIN. plications for their energy and food require- 1981. Strategie d'adaptation au froid chez le ments. Condor 83: 238-242. Manchot royal (subantarctique): comparaison STONEHOUSE,B. 1960. The King Penguin(Aptenody- avecle Manchot empereur(antarctique). Pp. 339- tes patagonicus).1. Breeding behaviour and de- 344 in CNFRA Colloque sur les ecosystemssub- velopment.Falkland IslandsDependencies Surv. antarctiques, 51 (P. Jouventin, L. Masse, and P. Sci. Repts. No. 23. Trehen, Eds.). URAMOTO,M. 1961. Ecologicalstudy of the bird KOOYMAN,G. L., R. W. DAVIS,J. P. CROXALL,• D. P. communityof the broad-leaveddeciduous forest COSTA. 1983. Diving depths and energy re- of central Japan. Misc. Repts. Yamashina Inst. quirementsof King Penguins.Science 217: 727. Ornithol. Zool. 3: 1-32. PENFOLD,V. 1979. Exhibition of penguins in the Montreal Aquarium. Intern. Zoo Yearbook 18: Received11 October1983, accepted26 March 1984. 70-72.

Egg Retrieval by Canada Geese:Apparent Interspecific Retrieval and Tests of Egg Displacement

DAVII• C. DUNCAN Departmentof Zoology,University of Alberta,Edmonton, Alberta T6G 2E9,Canada

Eggretrieval, an innatebehavioral pattern in which and Prevett's(1973) hypothesis that egg retrieval may birds roll displaced eggs into their nests by using occuronly after incubationhas begun, it is interest- their bills, wasfirst describedin detail in the Greylag ing to note that the pintail eggswere not "retrieved" Goose (Anser anser)(Lorenz and Tinbergen 1939). until after the goosehad completedlaying. Prevettand Prevett(1973) reported that egg retrieval To investigate egg retrieval behavior in Canada occurred in numerous species of ground-nesting Geese, egg displacementtests were conducted be- birds, including a number of species of Anseri- tween 13 and 17 April 1983 on geesenesting in the formes, but made no reference to this behavior in area of the observation.One egg per nest was taken Canada Geese (Branta canadensis).Kossack (1950: 644) from 34 nests and placed at one of the following thought it unlikely that CanadaGeese retrieved eggs, distances from the nest: 25, 50, 75, or 100 cm. The becausehe found eggs lying outside and yet near distance was measured from the center of the dis- their nests.This note reports:(1) an incident in which placed egg to the outer edge of the nest bowl. The a CanadaGoose apparently "retrieved" the eggsfrom displacedeggs were marked with indelible ink and a nearby Northern Pintail (Anasacuta) nest, and (2) positionedso as to be readily visible from the nest. the resultsof teststo confirmegg retrieval in Canada About 50% of the geesewere laying at the time of Geeseand to determinethe distanceover which they egg displacement;virtually all, however, had fin- would retrieve eggs. ished laying when the eggs were checked4-6 days On 24 April 1982,a pintail nest with four eggswas later. Of the 32 geesethat continued incubation,all found 45 cm from the edge of a Canada Goosenest 27 with eggs placed at 25-75 cm from the nest re- containing three eggs. The nestswere on an island trieved the egg (10 from 25 cm, 8 from 50 cm, and 9 about 35 km southeastof Brooks,Alberta. Two days from 75 cm). In one casethe egg was rolled to the later, the pintail nestcontained six eggsand the goose edge of the nest but not into the nest bowl. Four of nest contained five. When the nests were checked 4 the 5 eggs placed 1 m from the nest were retrieved. dayslater, the goosewas incubatingfive gooseeggs Prevett and Prevett (1973) found that 95 cm was about and five pintail eggs, having apparently rolled the the maximum distancethat eggs were retrieved by pintail eggsinto her nest. Only a small ball of nest Snow Geese(Chen caerulescens). The testsreported here material remained where the pintail nest had been. suggestthat 1 m may be approachingthe limit from On 17 May the goosenest containedonly the five which Canada Geesewill retrieve eggs. They may gooseeggs. A few small fragmentsof eggshell were not, however, retrieve eggsat much over 1 m; in 1983 found around the nest, and I surmisethat the pintail a Mallard (Anas platyrhynchos)nest, located 110 cm eggswere either depredatedby gulls[I observedCal- from a CanadaGoose nest, remained undisturbedby ifornia Gulls (Laruscalifornicus) and Ring-billed Gulls the goose.Kossack's (1950) impressionthat Canada (Larusdelawarensis) eating duck eggsbut very seldom Geesedo not retrieve eggs may have been basedon gooseeggs] or were accidentallybroken and subse- observationsof eggsthat were lying beyond the egg quently removed by the goose.In light of Prevett retrieval limit. The retrieval limit indicated here for October 19841 ShortCommunications 887 the western Canada Goose(B.c. moffitti)may differ LITERATURE CITED greatly from that of other racesof Canada Geeseif the limit is proportional to the size of the bird. GIROUX,J-F. 1981. Ducksnesting in associationwith The proximity of duck neststo goosenests report- CanadaGeese. J. Wildl. Mgmt. 45: 778-782. ed herein may not have been accidental, as some KOSSAC}C,C. W. 1950. Breeding habits of Canada ducks may be inclined to nest close to nesting geese Geeseunder refuge conditions.Amer. Midland Natur. 43: 627-649. to benefit from the goose'ssuperior ability to deter predators(Long 1970,Giroux 1981). Egg retrieval by LONG,R. J. 1970. A study of nest-siteselection by geesecan result in the destructionof duck clutches island-nesting anatids in central Alberta. Un- laid within a goose'sretrieval limit, and, consequent- publishedM.S. thesis.Edmonton, Alberta, Univ. Alberta. ly, there may be selectionfor ducks to situate their LORENZ, K., & N. TINBERGEN. 1939. Taxis und In- nestsat some optimal distance from goosenests. Information contained in this note was gathered stinkthandlungin der Eirollbewegungder Grau- with the supportof an operating grant to D. A. Boag gans.I. Z. Tierpsychol.2: 1-29. from the Natural Sciencesand EngineeringResearch PREVETT,J.P., & L. S. PREVETT.1973. Egg retrieval Council of Canada. I thank R. Cotter for assistance in by Blue Geese.Auk 90: 202-204. the field and D. A. Boagfor his helpful commentson Received9 November1983, accepted13 March 1984. the manuscript. R. M. Evans and an anonymous re- viewer also provided helpful suggestions.

Molts and Plumagesof Gadwalls in Winter

STUART L. PAULUS • BiologyDepartment, University of NorthDakota, Grand Forks, North Dakota 58202 USA

Previousstudies of Anatinae during the nonbreed- externallyand subjectivelycategorized the percent- ing seasonsuggested that the attainment of the ageof prealternatemolt completedby immatureand breeding (alternate)plumage may be related to the adult Gadwalls as 0-25% (early body molt), 26-50% time of pair formation (Weller 1965,McKinney 1970, (body molt nearly completed,lower rump molt un- Armbruster 1982). In these studies, however, no at- derway),51-75% (body molt completed,lower rump tempt was made to quantify the timing and se- molt nearly completed),and 76-100% (rump molt quencesof molt or to relate the timing of molt to the completed,tertials renewed and fully elongated,head age or sex of the individual. crest evident in males). The plumage sequenceof Gadwalls (Anasstrepera) A secondstudy involved the preparationof a pter- has been describedby Bellrose (1978), and Oring ylosis diagram, similar to that used by Billard and (1968) traced the molt sequenceof a captive flock of Humphrey (1972), for Gadwalls collectedon Rocke- Gadwallsover a 2-yr period. In this study I describe feller and Marsh Island SWR. From this diagram, I the molt sequenceof immature and adult birds win- determinedthe degreeof molt for the entire bird and tering in Louisianaand relate the timing of molt to for each body region by internal and external ex- age, sex,courtship activities, and energetics. amination of feathers and feather tracts, and I sub- Observations and collections of Gadwalls were jectivelycategorized the degreeas none, light (only conducted in southwest coastal Louisiana on Rocke- a few feathers growing), moderate (numerous new feller and Marsh Island StateWildlife Refuges(SWR), feathers growing), or heavy (nearly all feathers Sabine National Wildlife Refuge (NWR), and on pri- growing). Pterylosisdiagrams and plumage analyses vately owned lands within 20 km of RockefellerRef- were limited to adults, becauseonly a few immature uge.These areas have been described in Paulus(1982). birds were collected. I collected Gadwalls by shooting on Rockefeller Age and sex were determinedby internal exami- and Marsh Island SWRfrom November 1977through nation of the gonadsand bursaof Fabricius.The re- March 1978 and from hunters at Sabine NWR and lationship between the percentage of prealternate marshesadjacent to Rockefeller SWR from Novem- molt completed, courtship activities, and time of ber 1977 through early January 1978. Two studies pairing was determined during activity-budgetob- were conductedto determinemolt sequencesof Gad- servations of Gadwalls in Louisiana (Paulus 1984). walls in winter. First, I examined hunter-killed birds The prealternatemolt for most adult males began on the breeding grounds or while the birds were migratingsouth, and by late Januarythe prealternate •Present address:Department of Zoology-Ento- molt was completed(Table 1, Fig. 1). Major areasof mology,Auburn University, Auburn, Alabama36849 feather replacementfor adult malesduring fall were USA. the neck and humeral regions.Immature maleswere