Post-pleistocene dispersal in black-capped (Poecile atricapillus) and mountain (P. gambeli) chickadees, and the effect of social dominance on black-capped chickadee winter resource allocation

Abstract

This study investigates the phylogeographic structure and population genetics of two non-migratory, congeneric species: the black-capped chickadee (Poecile atricapillus) and the mountain chickadee (P. gambeli). Mitochondrial DNA (control region) sequences for both species, as well as microsatellite data for mountain chickadee, revealed a pattern of recent expansion with subsequent genetic differentiation, and limited geographic structure. Results suggest multiple New World glacial refugia: Newfoundland; a southern; Pacific Northwest and southeast U.S. refugia for black-capped chickadee ; and a central Rockies, and two western refugium(a) (southern California and central California) for mountain chickadee. West of the Rocky Mountains, both chickadee species show evidence of more recent diversification and phylogeographic structure. Mechanisms that may differentially affect one species versus the other (e.g., geomorphological barriers, species dispersal/recolonization models, life history traits) are also discussed.