Date of Award
Spring 5-6-2024
Document Type
Thesis
Degree Name
Bachelor of Arts
Department
Biology
First Advisor
Professor Iris Levin
Abstract
While female mate choice is well established, mutual choice may play a larger role in mate selection than recognized. Assortative mating is one potential outcome of mutual mate choice, and occurs in many avian systems. We asked whether North American barn swallows (Hirundo rustica erythrogaster) pair, mate, and interact socially with individuals of similar phenotype. We investigated patterns of assortativity in ventral plumage color, tail streamer length, wing length, mass, age, arrival date, and social interactivity for adult barn swallows breeding in Ohio and Colorado. Social interaction data came from proximity loggers, which recorded close contact between tagged individuals when birds were mating and laying eggs. Social pair formation was strongly constrained by arrival timing to the breeding colony since pairs formed between birds who arrived at similar times. Social pairs also tended to assort by age, because after-second-year birds typically arrive earlier than first-year breeders. In Ohio, where there is more variation in ventral plumage color, birds paired with individuals of similar plumage color, but only when we considered color relative to the colony- and sex-specific means. Barn swallows regularly engage in extra-pair copulations, and mating pairs in Ohio were more strongly assortative by ventral plumage color than social pairs. Birds also exhibited strong social network assortativity, interacting more often with individuals of both sexes who had similar phenotypes relative to the other birds in the colony. Investigation of assortative behavior beyond the level of the social pair provides a more complete understanding of the mating process and provides evidence for a mechanism maintaining the large variation in ventral plumage color in North American barn swallows.
Recommended Citation
Morosse, Omar J., "North American barn swallows (Hirundo rustica erythrogaster) pair, mate, and interact assortatively" (2024). Honors Theses. 881.
https://digital.kenyon.edu/honorstheses/881
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