AVIAN USE OF HABITAT CONFIGURATIONS CREATED BY FOREST CUTTING IN SOUTHEASTERN WYOMING

Timber harvest in western forests initially interrupts large expanses of old-growth forest with smaller clearcuts. Although the vegetation within the remaining old-growth is still present and intact, there is an increase in forest edges and a reduction in the continuity of the original forest. We compared avian species composition and abundance in four pairs of sites, each pair having an uncut site and one fragmented by small clearcuts in southeastern Wyoming. Fragmented stands were interrupted with strip or patch clearcuts. The abundance of species was also compared among the habitat configurations present on these sites such as forest interiors, meadow edges and clearcuts. Of 16 bird species, Brown Creepers (Certhia americana) and Hermit Thrushes (Catharus guttatus) were the most negatively influenced by fragmentation; Pine Siskins (Carduelis pinus) were the most positively influenced by fragmentation. The distribution of birds among forest interiors and edges suggested the responses to fragmentation were not generally mirrored by preferences or avoidance of forest edges and interiors. The effect of fragmentation may result from the loss of resources from clearcutting or preferences for the type of habitat adjacent to the forest stand (meadows or clearcuts).