Figure 1. Sampling locales of Loggerhead Shrike feathers used for this study.

A tail feather was obtained for DNA assays and a feather clipping of the first primary feather was obtained for stable hydrogen isotope analysis from each individual sampled to quantify genetic population structure and develop a species-specific isoscape, respectively. Areas in which samples were selected to test Bayesian methodology for assigning individuals to a probable origin using separate assignment analysis of microsatellite data as priors for analysis of δ²H_f data are noted as ‘breeding and validation’ areas.