The role of corticosterone and corticosteroid-binding globulin in reproduction of red-legged kittiwakes (Rissa brevirostris)

Abstract

The goal of this study was to determine to what extent, and by what physiological and behavioral mechanisms, avian reproductive performance is related to environmental variability. Specifically, I explored relationships between components of the physiological stress response, reproductive behavior, and reproductive performance in the red-legged kittiwake (Rissa brevirostris), a long-lived seabird. I found that individuals respond to food-related stress by altering levels of both corticosteroid-binding globulin (CBG) and the primary avian glucocorticoid, corticosterone (Cort). I also found a negative association between breeding adults' Cort concentrations and population-level reproductive success; although no such association existed between CBG and reproductive success. The relationship between Cort and reproductive performance does not appear to result from Cort concentrations affecting an adult's decision to initiate or forego reproduction in a given year. In conclusion, this study suggests that environmentally-induced physiological stress affects reproductive success of red-legged kittiwakes, although the behavioral mechanism remains unknown.