Do Olive-backed Orioles and Green Orioles hybridize in Australia? A genomic assessment with taxonomic notes

Geographic overlap of Olive-backed Oriole O. sagittatus and the Green Oriole O. flavocinctus is extensive in northern Australia, but they generally are separated by habitat. They overlap in New Guinea, however, where their habitat distinction is much reduced. Genetic methods in an earlier study detected unexpected hybridisation between the two species in New Guinea. Here, we ask whether hybridisation between the two species may have gone unnoticed in northern Australia, whether genetic methods again may detect it, and whether this may relate to habitat management and conservation. We find no evidence for hybridisation in Australia and conclude that its occurrence in New Guinea is indeed likely related to the reduced habitat distinction between the two species there relative to their range in Australia. We also examine taxonomic corollaries of our genomic data.