Do Golden-cheeked Warblers Select Nest Locations on the Basis of Patch Vegetation?

Abstract

Abstract Proper management of endangered species requires an understanding of habitat use at a variety of spatial scales, and information on nesting habitat is especially important in that regard. We examined vegetation features associated with nest patches of the Golden-cheeked Warbler (Dendroica chrysoparia), a federally endangered migrant songbird that breeds only in central Texas. We used a spatially paired design to measure 13 vegetation variables at 43 nests and at an equal number of randomly chosen nonuse patches, one located near each nest. Canopy closure was greater at nest patches than at nonuse patches. However, none of the other vegetation variables differed between a nest patch and its paired non-use patch on the same territory, despite high power to detect such differences. In contrast, 8 of the 13 variables exhibited significant variation among territories. For all 13 variables, effect size was substantially greater for variation between territories than for variation between nest patches and their paired nonuse patches. Lack of within-territory variation may reflect the scale at which vegetation varies in that habitat. Such a result suggests that territory selection may be more important than nest-patch selection in this species.