Date of Award

Spring 5-4-2026

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Biology

First Advisor

Iris Levin, PhD

Abstract

Biparental care is common in avian taxa but investment is often unequal between the sexes. The factors determining parental investment are not fully understood, but there are three main explanatory frameworks: the good parent, differential allocation, and trade-off hypotheses. We tested these three hypotheses using video recordings of feeding, nest time, and brooding behavior in a large colony of barn swallows (Hirundo rustica ethryogaster). We ran generalized linear models to explain parental care according to individual and mate phenotype and mate parental effort. We found support for differential allocation both in individual feeding, which responded strongly to mate effort in both sexes, and in female brooding, which responded to mate ventral plumage color, a predictor of reproductive success in this system. We also found support for the good parent hypothesis in female brooding, as the behavior was related to individual ventral color. There were also trade-offs between parental behaviors, particularly between female brooding and feeding. Our results suggest that parental care is coordinated within pairs. We have some evidence that phenotypic traits may signal potential parental investment, but effort seems to depend more on mate quality and behavior. Future work should manipulate individual care to isolate the sex roles in the matching of parental effort that we observed. Additionally, more attention should be devoted to brooding which is an understudied but important contributor to reproductive success.

Rights Statement

All rights reserved. This copy is provided to the Kenyon Community solely for individual academic use. For any other use, please contact the copyright holder for permission.

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