Making contact: a population genetic analysis of warbling vireos (Vireo gilvus) in western North America

Abstract

This thesis examined range wide population genetic structure, morphological differences, and hybridization among three morphologically cryptic subspecies of warbling vireo (Vireo gilvus). MtDNA and microsatellite markers show genetic differences between the eastern, gilvus, and two western, swainsonii and brewsteri, subspecies, while genetic differences between the two western subspecies were detected only with microsatellite markers suggesting their separation is recent. Microsatellite genetic groups do not correspond to current taxonomic range distributions of the two morphologically similar western subspecies. A low frequency of hybridization between gilvus and swainsonii in Alberta suggest strong reproductive isolating barriers. A wide, unreported contact zone between swainsonii and brewsteri in southern British Columbia through western Montana had a high frequency of hybridization, where genetic composition of hybrids appears related to habitat and elevation. Molecular markers are a crucial tool in recognizing cryptic biodiversity for taxonomic and conservation implications.