Factors driving Adelie penguin chick size, mass and conditio

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TitleFactors driving Adelie penguin chick size, mass and condition at colonies of different sizes in the southern Ross SeaAbstractBody size, mass and condition can affect an organismÅ› ability to cope with variation in resource availability or metabolic demand, particularly as juveniles reach independence. It follows that changes to parental provisioning efficiency (size and frequency of meals) through intraspecific competition or environmental conditions that affect prey availability may affect chick size, mass and condition and ultimately post-fledging survival. We examined how AdÃ©lie penguin chick size, mass and condition varied among colonies of different sizes on Ross Island during a 15 yr period of high environmental variability and varying intraspecific competition. Aiding the study was a natural experiment in which the presence of 2 giant icebergs midway through the study abnormally increased sea ice concentration (SIC), altering adults Ìaccess to food. Concurrently, the colonies were rapidly increasing in size; based on previous work, this indicated increased trophic competition near colonies, a trend likely indicating a changing food web in the greater region. Results showed that increased amounts of sea ice, which reduced the ability of adults to access food, had a negative effect on the size and mass of chicks. However, a greater proportion of fish (vs. krill) in the diet had a positive effect on chick size. Moreover, in some cases, increased intraspecific competition may be a more important driver of provisioning rate and chick size than abiotic factors, with chicks showing the effects of reduced food delivery at larger colonies. Understanding these patterns will allow better understanding of how factors such as climate change and altered food webs may affect AdÃ©lie penguin populations. Copyright Inter-Research 2015.AcknowledgementsA.L.W., P.OBÌ.L., B.J.K., K.B. and P.R.W. were funded by New ZealandÅ› Foundation for Research, Science and Technology (C09527, C09X0510) and Ministry of Science and Innovation (C01X1001) and Landcare Research grants, with logistic support from Antarctica New Zealand. D.G.A., G.B., K.M.D., S.J. and A.L. were supported by NSF grants (0440643 and 0944411), and the US Antarctic Program. Our thanks go to the large number of field support staff who assisted this study over the years. We also thank M. Pinkerton, W. Fraser and the members of the New Zealand Antarctic Fisheries Working Group for review of the paper. All field work was conducted under a series of Antarctic Conservation Act permits and NZ and US Animal Ethic permits. Point Blue contribution #1994.Funding Details0440643, NSF, National Stroke Foundation; 0944411, NSF, National Stroke Foundation

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1st AuthorWhitehead, A.AuthorWhitehead, A.Lyver, P.Ballard, G.Barton, K.Karl, B.Dugger, K.Jennings, S.Lescroel, A.Wilson, P.Ainley, D.Year2015JournalMarine Ecology Progress SeriesVolume523Pages199-213DOI10.3354/meps11130URLhttps://www.scopus.com/inward/recor.....cbb560f4ab79d21179fd19a3bKeywordsbirdbody massbody sizeflightlessnessfood webintraspecific competitionjuvenileprey availabilityresource availability, Ross SeaSouthern Ocean, Spheniscidae, rank5Author KeywordsAdelie penguinChick growthDiet variabilityIntraspecific competitionProvisioning efficiency

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TypeArticleCitationWhitehead, A., Lyver, P., Ballard, G., Barton, K., Karl, B., Dugger, K., Jennings, S., Lescroel, A., Wilson, P. and Ainley, D. (2015) Factors driving Adelie penguin chick size, mass and condition at colonies of different sizes in the southern Ross Sea. Marine Ecology Progress Series, 523: 199-213 doi:10.3354/meps11130 IdentifierWhitehead2015Relevancerank5