Habitat and landscape correlates of presence, density, and species richness of birds wintering in forest fragments in Ohio

We investigated the distribution of wintering woodland bird species in 47 v ery small, isolated, woodland fragments (0.54-6.01 ha) within an agricultur al landscape in north-central Ohio. Our objectives were to determine correl ations between temporal, habitat, and landscape variables and avian presenc e, density, and species richness within the smallest woodlots occupied by s uch species. Our results suggest that even common species are sensitive to variation in habitat, landscape, and season. Woodlot area explained the mos t variation in presence, density, and species richness. Shrub cover was als o an important predictor variable for presence of the smallest resident bir ds. Shrub cover might function as both a refuge from predators and as a win dbreak, reducing thermal costs in a flat, open landscape. Landscape factors related to isolation and connectedness were also correlated with species p resence and density. The species composition of the community changed throu gh the winter, as did the density of individual species, suggesting that th e winter season may play an important role in determining the distributions of bird populations across woodlots. The models presented here for Ohio bi rds in this specific landscape may have biological inference for other spec ies in similar landscapes.