Investigating potential introgression between two North American passerines in western Canada

Speaker: Aaron Veale

Hybridization may increase when one species is rarer than the other (e.g., when one species does not have an established population, in endangered, or is on the edge of its range). With the eastward range expansion of Western Bluebirds (Sialia mexicana), territory originally held solely by Mountain Bluebirds (Sialia currucoides), brings the two species into contact. Both are sexually dimorphic birds and obligate secondary cavity nesters, preferring open woodland habitat where they feed on terrestrial insects. The low initial population density of Western Bluebirds in Alberta may cause scarcity in mate availability, leading to competition for limited mating opportunities with Mountain Bluebirds. Although distinct species, pairings between the two results in viable, fertile offspring. Using next-generation sequencing, the aim of my study is to establish the frequency of heterospecific mating, analyze areas of overlap for both first generation and advanced hybrids, and detect genetic introgression in Mountain Bluebird populations.