Learning has an important influence on species recognition in birds. Young songbirds learn songs, and in some cases other species-specific features soon after hatching. Together with lab member Emily Hudson, we are addressing how this learning process affects the evolution of reproductive isolation between a pair of sparrow species: white-crowned sparrows (Zonotrichia leucophrys) and golden-crowned sparrows (Z. atricapilla). These birds share habitat in some populations in Alaska and British Columbia (see photo), yet seems to rarely hybridize. However, a previous phylogenetic study (e.g., Weckstein et al. 2001) suggests that gene introgression has occurred between some populations but not others. Jason Weckstein and I are currently collaborating to dig deeper into the evolutionary history of this species pair.
Our goals are two-fold: (a) to determine, in detail, how young birds are predisposed to learn songs and species-specific features of their own species while living in close proximity to closely related heterospecifics, and (b) to understand how genetic isolation, past hybridization, and ecological competition contribute to the evolution of species recognition.