Buford, E.W., D.E. Capen, and B.K. Williams. 1996. Distance sampling to estimate fledging brood density of forested birds. The Canadian Field-Naturalist 110:642-648.
Abstract
Research on the status of avian communities often relies on estimates of abundance, but does not always consider demographic factors such as productivity. We introduce the application of a distance-sampling technique for estimating brood density of fledgling birds in forested habitats. During 1993 and 1994, we conducted 60 line-transect surveys on 10 sites in the Green Mountain National Forest in Vermont. Sites were divided into two groups, which allowed us to test for differences in fledgling density between groups. We detected 508 broods representing 38 species. Using standard distance-sampling procedures, we estimated densities of 0.576 (C.V. = 11.89) and 0.513 (C.V. = 12.54) broods per hectare. Density was not statistically different between groups. As with other survey methods, distance sampling favors easily detected species; however, line-transect density of fledglings is less obtrusive and less labor-intensive than mist-netting or nest searches, and can contribute important information to studies of avian communities.Research on the status of avian communities often relies on estimates of abundance, but does not always consider demographic factors such as productivity. We introduce the application of a distance-sampling technique for estimating brood density of fledgling birds in forested habitats. During 1993 and 1994, we conducted 60 line-transect surveys on 10 sites in the Green Mountain National Forest in Vermont. Sites were divided into two groups, which allowed us to test for differences in fledgling density between groups. We detected 508 broods representing 38 species. Using standard distance-sampling procedures, we estimated densities of 0.576 (C.V. = 11.89) and 0.513 (C.V. = 12.54) broods per hectare. Density was not statistically different between groups. As with other survey methods, distance sampling favors easily detected species; however, line-transect density of fledglings is less obtrusive and less labor-intensive than mist-netting or nest searches, and can contribute important information to studies of avian communities.