Whole-Genome Analysis of Introgression Between the Spotted Owl and Barred Owl ( Strix occidentalis and Strix varia, Respectively; Aves: Strigidae) in Western North America

Abstract

As the barred owl ( Strix varia; Aves: Strigiformes: Strigidae) expands throughout western North America, hybridization between barred and spotted owls ( Strix varia and S. occidentalis, respectively), if abundant, may lead to genetic swamping of the endangered spotted owl. We analyzed low-coverage, whole-genome sequence data from fifty-one barred and spotted owls to investigate recent introgression between these two species. Although we obtained genomic confirmation that these species can and do hybridize and backcross, we found no evidence of widespread introgression. Plumage characteristics of western S. varia that suggested admixture with S. occidentalis appear unrelated to S. occidentalis ancestry and may instead reflect local selection.