Morepork though he followed Mees in treating them as a single species. Janette Norman and colleagues tested the cytochrome "b" DNA of three subspecies (as well as the powerful and rufous owls) to ascertain whether the closest relative was used in breeding with the last surviving female of the Norfolk boobook. They discovered that although the Norfolk boobook was similar in plumage to the Tasmanian boobook, it was genetically much closer to the New Zealand subspecies. In fact, the two were so close genetically that they considered whether the Norfolk boobook should be recognised as a separate taxon at all, although
Southern boobook August to October in Queensland, from September to November in New South Wales and southern Western Australia, July to September in central and northern Western Australia, in October and November in Victoria, and in September to December in South Australia. The southern boobook nests in holes in trees between 1 and 20 m (3–70 ft) above the ground. The holes are generally vertical, and mostly in eucalypts, though other trees such as coast banksia ("Banksia integrifolia") have been recorded. Some sites are reused by the species for up to 20 years, especially if broods have been successfully raised in them