| Abstract: | We investigated temporal and spatial variability in the diet of chick-provisioning Ade??lie Penguins (Pygoscelis adeliae) breeding at all colonies within one isolated cluster in the southwestern Ross Sea, Antarctica, 1994-2000. We wished to determine if prey quality explained different population growth and emigration rates among colonies. Diet composition was described both by conventional means (stomach samples) and by analysis of stable isotopes in chick tissues (toenails of individuals killed by skuas [Stercorarius maccormicki]). Diets were similar among the four study colonies compared to the disparity apparent among 14 widely spaced sites around the continent. Calorimetry indicated that fish are more energetically valuable than krill, implying that if diet varied by colony, diet quality could attract recruits and help to explain differential rates of colony growth. However, a multiple-regression analysis indicated that diet varied as a function of year, time within the year, and percent of foraging area covered by sea ice, but not by colony location. Stable isotopes revealed similarity of diet at one colony where conventional sampling was not possible. We confirmed that sea ice importantly affects diet composition of this species in neritic waters, and found that (1) quality of summer diet cannot explain different population growth rates among colonies, and (2) stable isotope analysis of chick tissues (toenails) is a useful tool to synoptically describe diet in this species over a large area. |
| Genre: | Article |
| ProdID: | 70025917 |
| Citation Author: | Ainley, D. G.; Ballard, G.; Barton, K. J.; Karl, B. J.; Rau, G. H.; Ribic, C. A.; Wilson, P. R. |
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| Citation End Page: | 106 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Condor |
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| Citation Number Of Pages: | 12 |
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| Citation Search Results Text: | Spatial and temporal variation of diet within a presumed metapopulation of Ade??lie Penguins; 2003; Article; Journal; Condor; Ainley, D. G.; Ballard, G.; Barton, K. J.; Karl, B. J.; Rau, G. H.; Ribic, C. A.; Wilson, P. R. |
| Citation Start Page: | 95 |
| Citation Volume: | 105 |
| Citation Year: | 2003 |
| Type: | citation/reference |
| Text: | Spatial and temporal variation of diet within a presumed metapopulation of Ade??lie Penguins; 2003; Article; Journal; Condor; Ainley, D. G.; Ballard, G.; Barton, K. J.; Karl, B. J.; Rau, G. H.; Ribic, C. A.; Wilson, P. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 2003 00:00 -0600 |
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