Southern boobook smallest owl on the Australian mainland, the southern boobook is long. The nominate subspecies is the largest. It has short, rounded wings and a short tail, with a compact silhouette in flight. Southern boobooks on the Australian mainland follow Bergmann's rule, in that birds from cooler and more southerly parts of the range tend to be larger. Thus, birds from the Canberra region weigh around while those from the Cape York Peninsula and Broome are around . Females tend to be a little larger and heavier than males, with males weighing and females . The southern boobook has generally dark
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