STREAMSIDE VERSUS UPSLOPE BREEDING BIRD COMMUNITIES IN THE CENTRAL OREGON COAST RANGE

Despite the perceived ecological and management significance of streamside areas in the moist coniferous and mixed deciduous-coniferous forests of the Pacific Northwest, there is little empirical data on the relative importance of streamside habitat to area avifauna. Consequently, we compared breeding bird species diversity, richness, evenness, and individual species' abundance between streamside and upslope areas in 6 mature, unmanaged forest stands in the central Oregon Coast Range, 1988-89. Bird community composition and structure differed between streamside and upslope areas. Species diversity, richness, total bird abundance, and the abundance of 5 species were greater (P less-than-or-equal-to 0.078) along upslope transects; 2 common species were more abundance (P less-than-or-equal-to 0.059) along streams. Upslope areas contributed 61% of the total number of birds detected and exclusively contributed 33% of the species; whereas streamsides exclusively contributed only 9% of the species. Vegetation structure and composition may have been responsible for observed bird distributions. Management of riparian areas alone (e.g., riparian set-asides) may not meet the needs of several bird species. A landscape-level approach that considers both upslope and riparian habitat in conjunction may be more effective in meeting the need of the entire breeding bird community. Moreover, our results highlight the need to reconceptualize streamside values for terrestrial birds in moist coniferous and mixed coniferous-deciduous forests of western Oregon.