Southern boobook taxa (southern plus Tasmanian boobooks and moreporks) as a single species. Examining both morphological and genetic (cytochrome b) characters in 2008, German biologist Michael Wink and colleagues concluded that the southern boobook is distinct from the morepork and Tasmanian boobook (which they proposed to be raised to species status as "Ninox leucopsis"), and that it is instead the sister taxon to the barking owl ("N. connivens"). A 2017 study by Singapore-based biologist Chyi Yin Gwee and colleagues analysing both multi-locus DNA and boobook calls confirmed a sister relationship of "N. n. novaeseelandiae" and "N." ("n.") "leucopsis" and their close relationship
Norfolk boobook km²) Mt Pitt section of the Norfolk Island National Park. Boobooks breed in tree hollows. Recorded clutch sizes from Norfolk Island range from one to three eggs, with two being usual. Boobooks feed on small vertebrates, especially birds and mammals, as well as invertebrates. The population of the Norfolk boobook declined with the clearance and modification of its forest habitat, especially the felling of large trees with suitable hollows for nesting in. There was also competition for nest hollows with feral honey bees and introduced crimson rosellas. By 1986 the population had been reduced to a single female bird, named