The population genetics of non-migratory Allen's Hummingbird (Selasphorus sasin sedentarius) following a recent mainland colonization

Allen's Hummingbird comprises two subspecies, one migratory (Selasphorus sasin sasin) and one non-migratory (S. s. sedentarius). The non-migratory subspecies, previously endemic to the California Channel Islands, apparently colonized the California mainland on the Palos Verdes Peninsula some time before 1970, and now breeds throughout coastal southern California. We sequenced and compared populations of mainland non-migratory Allen's Hummingbird to Channel Island populations from Santa Catalina, San Clemente, and Santa Cruz Island. We found no evidence of founder effects on the mainland population. Values of nucleotide diversity on the Channel Islands were lower than those on the mainland. There were low levels of divergence between the Channel Islands and the mainland, although Santa Cruz Island was the most genetically distinct. Ecological niche models showed that rainfall and temperature variables on the Channel Islands are similar in the Los Angeles basin, and predicted continued ex...