Southern boobook

Appearance

The smallest owl on the Australian mainland, the southern boobook is anywhere from 27 to 36 cm long. The nominate subspecies is the largest. Southern boobooks on the Australian mainland follow Bergmann's rule, in that birds from more southerly parts of the range tend to be larger. Thus birds from the Canberra region weigh around 300 g while those from Cape York and Broome are around 200 g. However, the Tasmanian boobook and New Zealand morepork are also small.

The southern boobook has generally brown head and upperparts, with white markings on the scapulars and spots on the wings. Its head lacks tufts common in other owls, and has a paler facial disk with darker feathers behind the eyes. The eyes have been described as grey-green, green-yellow, or even light hazel, distinct from the Tasmanian and New Zealand species that have golden eyes. The underparts are paler, ranging from buff to cream, and are streaked with brown. The overall colour is variable and does not appear to correspond to subspecies or region. In northern and central Australia, Mayr found that the colour of the plumage appears to correlate with the rainfall or humidity, paler birds being found in three disjunct areas, each around 1600 km away from the other two: the western Kimberley and Pilbara, Sedan on the Cloncurry River, and around Ooldea, with darker birds found on Cape York and Melville Island.

Naming

Eleven subspecies are recognised:
⤷ ''Ninox boobook boobook'', the nominate subspecies, is found on the Australian mainland, from Southern Queensland, through New South Wales and Victoria into South Australia.
⤷ ''Ninox boobook halmaturina'' is found on Kangaroo Island. It is sometimes included in the nominate subspecies. It has dark brown underparts with reddish-brown rather than white markings.
⤷ ''Ninox boobook rotiensis'' is found on Rote Island in the Lesser Sunda Islands.
⤷ ''Ninox boobook fusca'' is found on Timor, Roma and Leti Islands in the eastern Lesser Sunda Islands. It has a more grey-brown plumage with no red tinge, unlike other subspecies.
⤷ ''Ninox boobook moae'' is found on Moa, Leti and Romang Islands in the Lesser Sunda Islands.
⤷ ''Ninox boobook plesseni'' is known only from a single specimen from Alor Island in the eastern Lesser Sunda Islands.
⤷ ''Ninox boobook cinnamomina'' is found on Tepa and Babar Islands in the eastern Lesser Sunda Islands.
⤷ ''Ninox boobook pusilla'' is from southern lowlands New Guinea.
⤷ ''Ninox boobook remigialis'' is found on the Kai Islands in the Lesser Sunda Islands.

⤷ ''Ninox boobook ocellata'' is found across northern Australia, Western Australia and western South Australia, as well as Savu near Timor. It is generally lighter-coloured than other mainland boobooks, though occasional dark-plumaged individuals are seen. Birds from Melville Island are small and generally dark, and were previously classified as a separate subspecies ''melvillensis''. Birds from southwestern Australia north to Tantabiddy on the North West Cape and Glen Florrie on the Ashburton River are relatively dark with more uniform rufous-brown underparts. Mees classified them as a separate subspecies ''rufigaster''. Mayr classified the lightest birds of northern Australia as ''arida'', medium toned birds as ''mixta'' and darker ones ''macgillivrayi''. All these taxa are regarded as ''ocellata''.
⤷ ''Ninox boobook lurida'', also known as the red boobook, is from north Queensland, and sometimes considered a separate species.

Distribution

The southern boobook is found across Australia, except in the most arid desert regions, and into southern New Guinea, Roti, Timor and surrounding islands in Indonesia. It is found in a wide range of habitats, from forest and open woodland to scrubland and semi-desert areas. It has adapted to landscapes altered by human activity and is found in farmland and suburban areas as long as there are some scattered trees.

Habitat

The southern boobook is found across Australia, except in the most arid desert regions, and into southern New Guinea, Roti, Timor and surrounding islands in Indonesia. It is found in a wide range of habitats, from forest and open woodland to scrubland and semi-desert areas. It has adapted to landscapes altered by human activity and is found in farmland and suburban areas as long as there are some scattered trees.

Reproduction

The southern boobook nests in holes in trees, anywhere from 1 to 20 m above the ground.

Food

The southern boobook generally preys on insects, particularly nocturnal beetles and moths, mice, and birds the size of a house sparrow. A higher proportion of its diet is invertebrates compared with other Australian owls. Fieldwork in the vicinity of Canberra found that vertebrates made up more of the diet in autumn and winter. A study in Victoria found that larger animals were eatern, including Baillon's crake, common ringtail possum and feral rabbit. It uses a fence, branch or telegraph pole as a perch or vantage point to hunt from.