POPULATION GENETICS OF THE GALÁPAGOS HAWK (BUTEO GALAPAGOENSIS): GENETIC MONOMORPHISM WITHIN ISOLATED POPULATIONS

Abstract Because of their smaller size and isolation, island populations tend to be more divergent and less genetically variable than mainland populations. We collected DNA samples from nine Galapagos Hawk (Buteo galapagoensis) island populations, covering the species’ entire range. Neutral minisatellite DNA markers were used to calculate within-island genetic diversity and between-island genetic differentiation (FST). Typically, these markers mutate too quickly to be informative in such studies. However, in very small, isolated populations, concerns about high mutational rate are obviated by the relative force of genetic drift. Individuals within islands had the highest levels of reported genetic uniformity of any natural bird population, with mean within-population band-sharing similarity values ranging from 0.693 to 0.956, increasing with decreasing island size. Galapagos Hawks exhibit cooperative polyandry to varying degrees across islands; however, we did not find an association between degree of pol...