Cooperative Fish and Wildlife Research Units Program: all
Education, Research and Technical Assistance for Managing Our Natural Resources

Identifying population genetic structure is useful for inferring evolutionary process as well as defining subspecies boundaries and/or conservation units that can aid in species management. The American Kestrel (Falco sparverius) is a widespread species with two described North American subspecies, (F. s. sparverius and F. s. paulus), the latter in the southeastern United States and the former across the remainder of its distribution. In many parts of their range, American Kestrels have been declining, but it has been difficult to interpret demographic trends without a clearer understanding of gene flow among populations. Here we sequence the first American Kestrel genome and scan the genome of 197 individuals from 12 sampling locations across the range of the two North American subspecies to identify population structure. To validate signatures of population structure and fill in sampling gaps across the breeding range we screen 192 outlier loci in an additional 376 samples from 34 sampling locations. Overall, our analyses support the existence of 5 genetically distinct lineages within American Kestrels—Eastern, Western, Texas, Florida, and Alaska.Interestingly, we find that while our genome-wide genetic data support the existence of previously described subspecies boundaries, genetic differences across the species’ range correlate more with putative migratory phenotypes (resident, long-distance, and short-distance migrants) rather than a priori described subspecies boundaries per se. Based on our results, we suggest the resulting five genetic lineages serve as the foundation for American Kestrel conservation and management in the face of future threats.