Recently, much research has focused on the effect of forest fragmentation on so-called "forest interior" bird species. Forest interior birds are dependent for breeding habitat on the central portions of large forest tracts; a decline in these species has been associated with a reduction in the size and quality of remnant forests (Robbins 1979; Whitcomb et al. 1981; and others). Fragmentation creates a greater proportion of edge habitat, resulting in increased nest predation (Wilcove 1985) and brood parasitism (Brittingham and Temple 1983). Ranney et al. (1981) have described edge-related changes in forest vegetation.