Intra-seasonal variation in foraging behavior among Adelie p

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TitleIntra-seasonal variation in foraging behavior among Adelie penguins (Pygocelis adeliae) breeding at Cape Hallett, Ross Sea, AntarcticaAbstractWe investigated intra-seasonal variation in foraging behavior of chick-rearing Adelie penguins, Pygoscelis adeliae, during two consecutive summers at Cape Hallett, northwestern Ross Sea. Although foraging behavior of this species has been extensively studied throughout the broad continental shelf region of the Ross Sea, this is the first study to report foraging behaviors and habitat affiliations among birds occupying continental slope waters. Continental slope habitat supports the greatest abundances of this species throughout its range, but we lack information about how intra-specific competition for prey might affect foraging and at-sea distribution and how these attributes compare with previous Ross Sea studies. Foraging trips increased in both distance and duration as breeding advanced from guard to creche stage, but foraging dive depth, dive rates, and vertical dive distances travelled per hour decreased. Consistent with previous studies within slope habitats elsewhere in Antarctic waters, Antarctic krill (Euphausia superba) dominated chick meal composition, but fish increased four-fold from guard to creche stages. Foraging-, focal-, and core areas all doubled during the creche stage as individuals shifted distribution in a southeasterly direction away from the coast while simultaneously becoming more widely dispersed (i. e., less spatial overlap among individuals). Intra-specific competition for prey among Adelie penguins appears to influence foraging behavior of this species, even in food webs dominated by Antarctic krill. Copyright 2010 Springer-Verlag.AcknowledgementsWe thank the following persons for planning and field assistance: Peter Dilks, Shulamit Gordon, Rachel Brown and Gus McAlister. Antarctica New Zealand provided extensive logistic support for the NZ Adelie Penguin Program (K122b) through their Latitudinal Gradient Program, while the US Antarctic Program supported members from the US Adelie Penguin Program (B031). This project was funded by the New Zealand Foundation for Research, Science and Technology (C09X0510) and Office of Polar Programs, National Science Foundation (OPP 0125608, 0440643). Draft manuscripts received valuable review from the editor and three anonymous referees. Reference to trade names does not imply endorsement of these products.

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1st AuthorLyver, P.AuthorLyver, P.MacLeod, C.Ballard, G.Karl, B.Barton, K.Adams, J.Ainley, D.Wilson, P.Year2011JournalPolar BiologyVolume34Number1Pages49-67DOI10.1007/s00300-010-0858-0URLhttps://www.scopus.com/inward/recor.....15f1a6bb6ac61f8dcb76c35bfKeywordsabundancebreeding populationcontinental shelfcontinental slopefood webforaging behaviorrearingseabirdseasonal variation, AntarcticaCape HallettEast AntarcticaRoss SeaSouthern Ocean, AvesDecapoda (Crustacea)Euphausia superbaEuphausiaceaPygoscelis adeliaeSpheniscidae, rank5Author KeywordsAd{\'e}lie penguinAntarctic krillAntarctic silverfishForagingIntra-seasonal competitionPack ice

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TypeArticleCitationLyver, P., MacLeod, C., Ballard, G., Karl, B., Barton, K., Adams, J., Ainley, D. and Wilson, P. (2011). Intra-seasonal variation in foraging behavior among Adelie penguins (Pygocelis adeliae) breeding at Cape Hallett, Ross Sea, Antarctica. Polar Biology, 34(1): 49-67