Influence of riparian buffer width on bird assemblages in Western Oregon

The goals of current management practices in riparian areas in the Pacific Northwest include protecting and maintaining habitat for terrestrial wildli fe. However, little is known about the use of riparian buffers by terrestri al wildlife, particularly how buffer width may affect abundance and species composition of wildlife communities. In this study, I compared bird assemb lages in logged and unlogged riparian areas along headwater streams and ass essed the relations between bird abundance and riparian buffer width. The a bundances of 4 species of forest-associated birds that were more abundant i n unlogged than in logged headwater riparian stands (Pacific-slope flycatch er [Empidonax difficilis], brown creeper [Certhia americana], chestnut-back ed chickadee [Poecile rufescens], winter wren [Troglodytes troglodytes]) in creased with increasing width of riparian buffers. However, 4 other species that also were more abundant in unlogged than logged riparian stands (Hamm ond's flycatcher [Empidonax hammondii], golden-crowned kinglet [Regulus sat rapa], varied thrush [Ixoreus naevius], hermit warbler [Dendroica occidenta lis]) were rarely observed in even the widest buffers sampled (40-70 m on 1 side of the stream). Although riparian buffers along headwater streams are not expected to support all bird species found in unlogged riparian areas, they are likely to provide the most benefit for forest-associated bird spe cies if they are >40 m wide, and density of large trees within buffers is n ot reduced by harvesting.