Phylogeography of the Galapagos hawk (Buteo galapagoensis):: A recent arrival to the Galapagos Islands

Galapagos hawks (Buteo galapagoensis) are one of the most inbred bird species in the world, living in small, isolated island populations. We used mitochondrial sequence and nuclear minisatellite data to describe relationships among Galapagos hawk populations and their colonization history. We sampled 10 populations (encompassing the entire current species range of nine islands and one extirpated population), as well as the Galapagos hawk's closest mainland relative, the Swainson's hawk (B. swainsoni). There was little sequence divergence between Gal pagos and Swainson's hawks (only 0.42% over almost 3 kb of data), indicating that the hawks colonized Galdpagos very recently, likely less than 300,000 years ago, making them the most recent arrivals of the studied taxa. There were only seven, closely related Galapagos hawk haplotypes, with most populations being monomorphic. The mitochondrial and minisatellite data together indicated a general pattern of rapid population expansion followed by genetic isolation of hawk breeding populations. The recent arrival, genetic isolation, and phenotypic differentiation among populations suggest that the Galdpagos hawk, a rather new species itself, is in the earliest stages of further divergence. (c) 2005 Elsevier Inc. All rights reserved.