96.1 Saturday, Jan. 7 Parental behavior and corticosterone during the breeding season in eastern bluebirds ( Sialia sialis) DAVIS, J.E.*; GUINAN, J.A.; Radford University; Radford University email@example.com
Breeding animals face a trade-off between investment in self and investment in offspring; too much investment in self can reduce offspring survival and fitness, while too much investment in offspring can increase individual mortality or decrease long-term reproductive success. Reproductive and stress-related hormones play an important role as mediators of this balancing act. Previous studies have correlated reductions in reproductive and parental investment with increased stress and elevated plasma corticosterone. In addition, the physiological and behavioral responses of an individual both influence and are influenced by the physiology and behavior of close social interactants, such as mates and offspring. Here we present both behavioral and hormonal data gathered from adult and nestling eastern bluebirds in southwestern Virginia across three consecutive breeding seasons with high nest failure rates. Our data demonstrate a negative relationship between female plasma corticosterone and female parental behavior, as well as a positive connection between female corticosterone and parental investment by males. These findings suggest that males may attempt to compensate for decreased maternal investment related to increased maternal stress. In contrast, little relation was found between parental corticosterone and offspring corticosterone or health. However, our data do suggest a positive relationship between parental feeding rates and overall nestling corticosterone. This may indicate that parents attempt to behaviorally buffer against increased nestling stress.