P-11 Effects of Eggshell Coloration on Egg Cannibalism Among Glaucous-Winged Gulls

Abstract

Egg cannibalism by gulls during the breeding season is a common source of reproductive loss for these birds. Fifty-five percent of egg loss on the Protection Island Glaucous-Winged Gull colony is due to cannibalism. Gulls commonly use their excellent eyesight to search for food, including eggs. We hypothesized that gull eggs with more typical coloration should have a smaller risk of cannibalism by neighboring gulls. In contrast to our hypothesis, ImageJ color analysis of 674 cannibalized and non-cannibalized eggs during the summer of 2015 demonstrated that unusually colored eggs were most likely to avoid cannibalism.

Acknowledgments

James L. Hayward, Shandelle M. Henson, and Robert Polski.

J. N. Honors Program.

National Science Foundation.

Thesis Record URL

https://digitalcommons.andrews.edu/honors/175

Start Date

3-2-2018 2:30 PM

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Mar 2nd, 2:30 PM

P-11 Effects of Eggshell Coloration on Egg Cannibalism Among Glaucous-Winged Gulls

Egg cannibalism by gulls during the breeding season is a common source of reproductive loss for these birds. Fifty-five percent of egg loss on the Protection Island Glaucous-Winged Gull colony is due to cannibalism. Gulls commonly use their excellent eyesight to search for food, including eggs. We hypothesized that gull eggs with more typical coloration should have a smaller risk of cannibalism by neighboring gulls. In contrast to our hypothesis, ImageJ color analysis of 674 cannibalized and non-cannibalized eggs during the summer of 2015 demonstrated that unusually colored eggs were most likely to avoid cannibalism.