Comparative foraging ecology of parental common murres (Uria aalge) and Atlantic puffins (Fratercula arctica) in response to changes in forage fish availability

Burke, Chantelle M. (2008) Comparative foraging ecology of parental common murres (Uria aalge) and Atlantic puffins (Fratercula arctica) in response to changes in forage fish availability. Masters thesis, Memorial University of Newfoundland.

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Abstract

To ensure successful reproduction, seabirds must make continuous and adaptive foraging decisions in the face of uncertain prey conditions. I compared the foraging behavior (foraging ranges and diet choices) of parental common murres and Atlantic puffins at a high density, offshore colony (Funk Island) during 2 years of different forage fish availability. In a poor food year (2005), characterized by an order of magnitude decline in forage fish densities and smaller fish, murres and puffins increased the mean distance they traveled to forage by 36% and preferentially selected larger fish. These responses show flexible foraging behavior, but significantly lighter murre fledglings in 2005 (203.0 ± 4.6 g) relative to 2004 (215.0 ± 3.9 g) suggests that specialized feeding on unpredictable prey can have consequences for reproductive success. Puffins that are generalist foragers and have multiple prey load capacity were more resilient to declines in prey availability.

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