Scale-dependent habitat selection by American Redstarts in aspen-dominatedforest fragments

We examined scale-dependent site occupancy of American Redstarts (Setophaga ruticilla) in forest fragments (2-140 ha in area) dominated by mature trem bling aspen (Populus tremuloides) in central Alberta, Canada. Vegetation wi thin territories, both adjacent to and away from nests, differed from veget ation in unoccupied fragments and within occupied fragments outside of terr itories. Territories contained higher densities of willow (Salix sp.), a ta ller shrub-layer, and lower densities of trembling aspen than other sites. Willow was the most frequently used plant species for nesting and foraging. Our results indicate that even within mature forest patches, American Reds tarts select disturbed areas dominated by early successional plant species.