Morepork they conceded the two were easily distinguishable in appearance, so maintained the three as subspecies; the Tasmanian boobook only diverged by 2.7% from the other two, while the powerful and rufous owls diverged by 4.4% from each other. Leading from this, the southern boobook was split from the Tasmanian boobook and morepork in volume 5 of the "", however several authors, including Les Christidis and Walter Boles, contested that the data had been misinterpreted from the Norman study, which had not sampled any Australian mainland boobooks at all. They treated the three taxa (southern, Tasmanian boobooks, and moreporks) as a
Penelope Diane Olsen Penelope Diane Olsen Dr Penelope Diane Olsen is an Australian ornithologist and author. She has worked with CSIRO as an experimental officer and an Honorary Research Associate as well as being an ARC Postdoctoral Fellow at the Australian National University. She is also internationally recognised as an expert on raptors and was involved in the conservation work on Norfolk Island for the Norfolk Island Boobook. She was President of the Australasian Raptor Association 1984–1989. In 1997 she was awarded the Royal Australasian Ornithologists Union's D.L. Serventy Medal for excellence in published work on birds in the Australasian region. Since 2003