Southern boobook their upperparts. The tips of their feathers are white and fluffy, remnants of the nestlings' down. These are worn away over time, persisting longest on the head. The feathers of the head, neck and underparts are fluffier overall. Immatures in their second and third year have plumage more like adults, though their crowns are paler and more heavily streaked. On mainland Australia, it could be confused with the barking owl or the brown hawk-owl ("Ninox scutulata"), a rare vagrant to the northwest, although the southern boobook is easily distinguished by its squat posture and distinctive pale border to its face
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