Data from: Population genetics and speciation of yellow-bellied, red-naped, and red-breasted sapsuckers (Sphyrapicus varius, S. nuchalis, and S. ruber)

The root of understanding speciation lies in determining the forces which drive it. In many closely-related species, including Sphyrapicus varius, S. nuchalis, and S. ruber, it is assumed that speciation occurred due to isolation in multiple Pleistocene refugia. We used genetic data from 457 samples at the control region, COI, and CHD1Z to examine rangewide population genetic structure and differentiation amongst these three species across each species’ breeding range. In addition, we modelled these species’ ecological niches for the Holocene (~6,000 ya), Last Glacial Maximum (~22,000 ya), and Last Interglacial (~120,000-140,000 ya) to determine if Pleistocene glaciations could have contributed to allopatric distributions, therefore allowing these groups to differentiate. Population genetic data show a potential Pleistocene refugium in Haida Gwaii, an east-west split among S. varius, and low genetic differentiation within each species. Our control region data show some polyphyly, while COI and CHD1Z data show differentiation among species using composite genotypes. Ecological Niche Modelling shows a large amount of niche overlap at each time period suggesting that S. varius, S. nuchalis, and S. ruber may not have been completely allopatric, and these species likely had repeated intermittent contact. Our data support the growing body of research that suggests differentiation despite gene flow