A flicker of hope: genomic data distinguish Northern Flicker taxa despite low levels of divergence

Next-generation sequencing technologies are increasingly being employed to explore patterns of genomic variation in avian taxa previously characterized using morphology and/or traditional genetic markers. The hybridization dynamics of the Northern Flicker complex have received considerable attention, primarily due to the conspicuous plumage differences among these birds and the geographically extensive hybrid zone between the Red-shafted (Colaptes auratus cafer) and Yellow-shafted (Colaptes auratus auratus) flickers in the Great Plains region of North America. However, no traditional molecular techniques have been able to differentiate these 2 morphologically well-defined taxa from one another, or conclusively from the closely related Gilded Flicker (Colaptes chrysoides). Here, we use a next-generation sequencing approach to assess the genetic diversity and evolutionary history of these 3 taxa. We confirm the overall low levels of differentiation found using traditional molecular marker...