PROVISIONING OF NESTLINGS BY MALE AND FEMALE YELLOW-BREASTED CHATS

Observations of parental feeding roles were made at 19 Yellow-breasted Chat (Icteria virens) nests during the 1994 breeding season in centra l Kentucky. Male and female chats fed nestlings at similar rates, and adult feeding rates were unaffected by brood size. The absence of any change in feeding rates with increased brood size suggests that food r equirements per nestling decrease as brood size increases, perhaps bec ause of differences in thermoregulatory costs. In contrast to the resu lts of many other studies, provisioning rates and load sizes (number o f prey delivered per visit) did not increase with nestling age. Howeve r, our observations at chat nests did not begin until nestlings were 3 or 4 days old. Studies of other species have revealed that 1-3 day ol d nestlings may be visited less frequently and provided with smaller l oads than older nestlings, and observations of nestling chats during t his early period might have revealed similar behavior.