Fig. 1

Predicted distributions of Audubon’s Warbler and Myrtle Warbler at the present time (a), Last Glacial Maximum (b), and Last Interglacial (c). The niche models were constructed by entering breeding records from the breeding bird survey (accessed at www. pwrc.usgs.gov/bbs) into MAXENT ver 3.2.2. (Phillips et al. 2006). Climatic data (19 layers) were obtained from the Worldclim bioclimatic database (Hijmans et al. 2005), and Maxent was set to use 30% of values for training. Distribution maps were coded to show either presence or absence based on a minimum threshold of predicted occurrence