EFFECTS OF LONG-TERM FOREST CLEAR-CU'Il"'ING ON WINTERING AND BREEDING BIRDS

ABSTRACr.-I examined the effects of even-aged clear-cutting (third cutting cycle) on wintering and breeding bird communities at the Barrens Grouse Habitat Management Area (HMA) in central Pennsylvania, 1987-1989. I tested the hypotheses that community structure and population abundance of wintering and breeding birds did not differ (1) among areas of the Barrens Grouse HMA that varied in extent of clear-cutting (0%, 50%, and 75% areas) or (2) among habitats of different age since clear-cutting on the treated sector (50% and 75% areas). These findings were compared to those obtained subsequent to a second cutting cycle. Abundance of 11 species of wintering birds did not vary (P > 0.05) among the three areas. Species richness of all species combined and of ground-shrub foragers was high in the 50% and 75% areas after the third cycle, largely because of additional brushy vegetation. Abundances of all species combined and of ground-shrub foragers were greater than expected in the 75% area but lower than expected in the 0% and 50% areas; abundance of sallier-canopy foragers was greater than expected in the 0% area and less in the 75% area. Two Neotropical migrants, Ovenbird (Seiurus aurocapillus) and Red-eyed Vireo (Vireo olivaceus), were more sensitive than other area-dependent species to increased fragmentation via forest clear-cutting resulting from the third cycle. I conclude that the creation of a mosaic of small (1 ha), even-aged stands for management of Ruffed Grouse (Bonasa umbellus) habitat does not have a detrimental long-term effect on most species of breeding and win