ABSTRACT
Abstract. Understanding how an animal species uses habitat at a landscape scale is critical in interpreting its ecology and behavior for use in conservation planning. We compiled a dataset of 28,822 location records for Golden-winged Warblers (Vermivora chrysoptera; n = 8,266) and Blue-winged Warblers (V. cyanoptera; n = 20,556) for a 13-year period (1998-2010) from ve sources. We modeled potential habitat of both species as a function of 17 variables related to climate, land cover, and elevation at the distribution-wide, regional, and subregional scales. We used a maximum entropy and ensemble forecasting approach to model the distribution of potential habitat. We evaluated model support with the area-under-the-curve and the true-skill-statistic criteria. We used the best supported models to project the species distribution and identify climate and habitat afnities. We used principal component analysis of dependent variables to further characterize habitats at the subregional scale. At the distribution-wide scale (2.5-km grid-cell size), the occurrence of Goldenwinged Warblers was associated with a cool, dry climate, at elevations from ~350 to 1,500 m and habitats comprised of at least 60% deciduous
forest cover. Regional correlates of the occurrence of Golden-winged Warblers included breeding season temperature, elevation, land-cover type, and forest type. In the Appalachian Mountains region, an elevation >500 m best predicted the occurrence of Golden-winged Warblers, whereas the distribution of aspen forest (Populus spp.) best predicted the occurrence of the species in the Great Lakes region. Models at ner subregional scales demonstrated similar associations; the occurrence of Golden-winged Warblers was associated with land-cover type, tree species composition, elevation, and temperature. The occurrence of Goldenwinged Warblers at the subregional scale was negatively associated with agriculture and human disturbance, which were more indicative of the occurrence of Blue-winged Warblers. Across all scales, the relative occurrence of Golden-winged Warblers was associated with deciduous forest at elevations >500 m and inversely associated with disturbed habitats. The opposite pattern was found for Blue-winged Warblers.
