Sexual Selection On Plumage Color In The Eastern Bluebird (Sialia Sialis)

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Callie Younginer (Creator)
Institution
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/
Advisor
Lynn Siefferman

Abstract: Species can exhibit exaggerated ornamentation that aids in the securement of mates. Sexual selection acts on variation in mating success and is prevalent in the color of plumage of many species of birds. Sexual dimorphism exists in species with conventional sex roles, but in species with comparable amounts of parental investment, females and males are often similarly colored. Eastern bluebirds (Sialia sialis) are a socially monogamous passerine with biparental care that display sexually dichromatic coloration; males have brilliant blue head and rump plumage and chestnut breasts while females have duller color. I used a 9-year dataset to explore evidence of sexual selection on plumage coloration in a southern Appalachian mountain population of eastern bluebirds. I found that females that were more-ornamented tended to lay eggs earlier in the season and had heavier body mass compared to the less-ornamented females. Among males, there were no significant relationships between color and reproductive success. My data suggest that, in this population, female plumage coloration may be driven by sexual selection and could be a signal of quality to conspecifics. Male mate choice for a high-quality partner or female competition over breeding resources may be driving this selection.

Additional Information

Publication
Honors Project
Younginer, C. (2018). "Sexual Selection On Plumage Color In The Eastern Bluebird (Sialia Sialis)." Unpublished Honors Thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2018
Keywords
Sexual selection, Female ornamentation, Structural coloration, Eastern bluebirds, Geographic variation

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