Brooding and provisioning of nestlings by male and female White-eyed Vireos (Vireo griseus)

Abstract

Most species of songbirds exhibit biparental care, but, for many taxa and species, little is known about the relative contributions of males and females in brooding and provisioning nestlings. Additional studies of the contributions of males and females in brooding and feeding nestlings are needed to better understand the respective roles of males and females as well as the factors that might contribute to interspecific variation in those roles. We examined the roles of adult male and female White-eyed Vireos (Vireo griseus) in brooding and provisioning nestlings in east-central Kentucky during the 1996 breeding season. Nests were located by monitoring adult behavior and checking likely nest sites. Once eggs hatched, nests were video-recorded to monitor the behavior of adults. Subsequent review of videos revealed that both male and female White-eyed Vireos brooded young and that males provisioned nestlings at higher rates than females. In contrast to males in many other species of songbirds, male White-eyed Vireos assisted in brooding young and provisioned nestlings at higher rates than their mates. One possible explanation for this is that low rates of extra-pair paternity might increase male confidence of their paternity status. Parental care provided by male White-eyed Vireos may also limit energy expenditure by their mates and increase the likelihood of females re-nesting if nests are predated or initiating second nesting attempts if initial attempts are successful.