Bird nesting ecology in a forest defoliated by gypsy moths

Acadian FLycatcher (Empidonax virescens. n = 55). Indigo Bunting (Passerina cyanea. n = 60). Eastern Towhee (Pipilo erythrophthalmus, n = 41), and Woo d Thrush (Hylocichla mustelina, n = 62) nests were monitored during 1995-19 96 in the eastern panhandle of West Virginia, at the Sleepy Creek Wildlife Management Area. The objective of this study was to relate the outcomes of bird nests to surrounding habitat characteristics in an area that experienc ed heavy tree mortality from prior defoliation by the gypsy moth (Lymantria dispar). Large (> 22.9 cm dbh) standing snags in the nest patch were not a ssociated with nest failure for any of the four bird species. Very large di ameter (> 38.1 cm dbh) live trees and snags and reduced canopy cover increa sed the chances of Brown-headed Cowbird (Molothrus ater) parasitism only fo r Indigo Buntings. Nest patches of all four species differed in vegetation characteristics from random plots in similar habitat, typically by having g reater densities of species' preferred nesting substrate in the nest patch. Gypsy moth defoliation, which can result in an increase in snags and opene d canopy, is not likely to be a devastating ecological event for shrub and sub-canopy nesting avian species. and can create more nesting habitat for m any species that use a dense forest understory.