The Great Horned Owl (Bubo virginianus) inhabits myriad habitats throughout the Americas and shows complex patterns of individual and geographic morphological variation. The owl family Strigidae is known to follow ecogeographic rules, such as Gloger's rule. Although untested at the species level, these ecogeographic rules may affect B. virginianus plumage coloration and body size. Previous studies have indicated that, despite this species' morphological variability, little genetic differentiation exists across parts of their range. This study uses reduced representation genome-wide nuclear and complete mitochondrial DNA sequence data to assess range-wide relationships among B. virginianus populations and the disputed species status of B. v. magellanicus (Magellanic or Lesser Horned Owl) of the central and southern Andes. We found shallow phylogenetic relationships generally structured latitudinally to the north of the central Andes, and a deep divergence between a southern and northern clade close to the Marañón Valley in the central Andes, a common biogeographic barrier. We identify evidence of gene flow between B. v. magellanicus and other subspecies based on mitonuclear discordance and F-branch statistics. Overall differences in morphology, plumage coloration, voice, and genomic divergence support species status for B. v. magellanicus.
Keywords: Bubo magellanicus; Bubo virginianus; Gene flow; Great Horned Owls; Mitonuclear discordance; Speciation; Strigidae; Ultraconserved elements.
©2023 Ostrow et al.