The Effects of Supplemental Feeding on Wintering Black-Capped Chickadees (Poecile Atricapilla) in Central Maine: Population and Individual Responses

In a remote area of central Maine, I established bird feeders stocked with black oil sunflower seeds to supplement the food of wintering Black-capped Chickadees (Poecile atricapilla). The chickadees discovered experimental feeders established in late October within two weeks; feeders established in mid-January were discovered more slowly. Weekly censuses showed that chickadee abundance was significantly higher in the presence of the feeders. Mark-recapture analysis revealed that as many as 110 and 70 chickadees were using the feeders at the two most intensively studied sites over 2-day periods. Ambient temperature had no influence on the rate at which banded chickadees visited the feeders. The visitation rate of banded chickadees was higher during the first third of the winter; perhaps competition for feeder access increased as increasing numbers of unbanded chickadees used the feeders as the season progressed. The frequency of feeder use varied markedly among the chickadees at each feeding site; this variation could not be explained by age of the birds (first-winter versus adult birds). Variability in feeder use was also apparent for individual birds over time.