Breeding bird abundance in bottomland hardwood forests: Habitat, edge, andpatch size effects

We studied breeding bird communities in extensive bottomland hardwood fores ts along the lower Roanoke River in North Carolina during 1992 and 1993. We documented a rich avian community and recorded exceptionally high densitie s of two species (Prothonotary Warbler Protonotaria citrea, Acadian Flycatc her Empidonax virescens), as well as modest densities of three species rare ly encountered elsewhere in the region (Cerulean Warbler Dendroica cerulea, Swainson's Warbler Limnothlypis swainsonii, American Redstart Setophaga ru ticilla). The effects of patch size and edge on bird abundance were small i n this forested landscape, but forest type had a large effect. We found hal f of the species analyzed to differ in abundance between the two primary ha bitat types, swamp forest and levee forest. In contrast, no species was con sistently more abundant at patch interiors than near edges, and only two fo rest birds were more common in large compared with small patches. Species a nalyzed included permanent residents, short-distance migrants, Neotropical migrants, and those identified as forest-interior and area-sensitive specie s in other studies. Our results suggest that the Roanoke River bottomland f orests may be functioning effectively as a reserve for a number of bird spe cies.