What makes a good parent? Sex-specific relationships between nest attendance, hormone levels, and breeding success in a long-lived seabird

Abstract

ABSTRACT Biparental care is found across taxa, but sex-specific contributions vary greatly both between and within species. Factors underlying intraspecific variation may include the phase of the reproductive cycle and sex-specific duties resulting in physiological or environmental constraints that differ between the sexes. For pair members to achieve high breeding success while maintaining good condition, parental duties should be well coordinated between mates. Avian breeding behavior is mediated by hormones such as prolactin and corticosterone, which link the internal and environmental parameters of individuals and regulate resource allocation. Using automated recording at the nest, we analyzed parental attendance by Common Terns (Sterna hirundo) in relation to sex, reproductive phase (incubation, chick rearing), time of day, breeding experience, and hormone levels, and related it to reproductive success. Nest attendance of females exceeded that of males, especially at night and during chick rearing. G...