Scale-dependent habitat selection by American Redstarts in aspen-dominated forest fragments

Abstract

We examined scale-dependent site occupancy of American Redstarts (Setophaga ruticilla) in forest fragments (2-140 ha in area) dominated by mature trembling aspen (Populus tremuloides) in central Alberta, Canada. Vegetation within territories, both adjacent to and away from nests, differed from vegetation in unoccupied fragments and within occupied fragments outside of territories. Territories contained higher densities of willow (Salix sp.), a taller 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 Redstarts select disturbed areas dominated by early successional plant species.