Date of Thesis

Spring 2024


Black-legged kittiwake (Rissa tridactyla) chicks engage in competition and aggression from first-hatched alpha (ɑ) chicks towards the beta (β) chicks, which can lead to facultative siblicide. Previous research has focused on chick behavior; here I investigate how and when parents respond to chick aggression and begging, and the consequences of these interactions. Because (1) chick sex may influence parental fitness, and (2) male and female adults may invest in reproduction differently, I tested the hypothesis that parent:chick interactions are affected by both parent and chick sex. Female kittiwakes may invest less during chick rearing, generating the prediction that they will be less responsive to chicks to preserve their own fitness. Kittiwakes also rear more daughters than sons during poor food conditions, since they are presumably less energetically costly than male chicks. In the current study, 28 two-chick nests with known-sex parents were recorded for one hour each at ɑ chick age five. Adult and chick behaviors were quantified, and ɑ chicks were genetically sexed. Although chick behavior rates did not differ by sex, male parents tended to be more responsive to female chick aggression and begging compared to male chicks, whereas female parents tended to be more responsive to male chick aggression, supporting my initial hypothesis regarding the effects of sex on parent:chick interactions, while providing new evidence of distinctive parental roles of male and female kittiwakes. My work is one of the first studies of parent-chick interactions that consider the role of both parent and chick sex.


facultative siblicide, birds, behavior, black-legged kittiwakes, parent-offspring conflict

Access Type

Honors Thesis (Bucknell Access Only)

Degree Type

Bachelor of Arts



First Advisor

Z Morgan Benowitz-Fredericks

Second Advisor

Reggie Gazes

Third Advisor

David Evans