Bird communities in commercially thinned and unthinned Douglas-fir stands of western Oregon

We compared abundance and diversity of breeding and winter birds between commercially thinned and unthinned 40- to 55-year-old Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Ranges. Abundance of breeding birds was greater in thinned stands. Bird species richness was correlated with habitat patchiness and densities of hardwoods, snags, and conifers. During the breeding season, Hammond's flycatchers (Empidonax hammondii), hairy woodpeckers (Picoides villosus), red-breasted nuthatches (Sitta canadensis), dark-eyed juncos (Junco hyemalis), warbling vireos (Vireo gilvus), and evening grosbeaks (Coccothraustes vespertinus) were more abundant in thinned than unthinned stands. Pacific-slope flycatchers (Empidonax difficilis) were more abundant in unthinned stands. Golden-crowned kinglets (Regulus satrapa), gray jays (Perisoreus canadensis), and black-throated gray warblers (Dendroica nigrescens) were more abundant in unthinned than thinned stands, but these patterns were inconsistent between seasons, regions, or years. Stand-scale habitat features were associated with the abundance of 18 bird species.