page_title: Powerful owl
section_title: Diet
hierarchical_section_title: Powerful owl / Behaviour / Diet
caption_attribution_description: English: Powerful Owl (Ninox strenua) holding prey near North Head, Sydney Harbour NP, Australia
context_page_description: The powerful owl is a species of owl native to south-eastern and eastern Australia, the largest owl on the continent. It is found in coastal areas and in the Great Dividing Range rarely more than 200 km inland. The International Union for Conservation of Nature Red List of Threatened Species also refers to this species as the powerful boobook. An apex predator in its narrow distribution, the powerful owl is often an opportunist like most predators, but generally is dedicated to hunting arboreal mammals, in particular small to medium-sized marsupials. Such prey can comprise about three-quarters of their diet. Generally, this species lives in primary forests with tall, native trees, but can show some habitat flexibility when not nesting. The powerful owl is a typically territorial raptorial bird that maintains a large home range and has long intervals between egg-laying and hatching of clutches. Also, like many types of raptorial bird, they must survive a long stretch to independence in young owls post-fledging.
context_section_description: The powerful owl is the top nocturnal predator of the forests and woodlands in its range. About 75% of the diet of the powerful owl is made up of arboreal mammals. Its diet consists largely of arboreal marsupials such as the greater glider (Petauroides volans), ringtail possums (Pseudocheiridae), brushtail possums (Trichosurus spp.), koala (Phascolarctos cinereus), sugar glider (Petaurus breviceps) and feathertail gliders (Acrobates pygmaeus). These prey species vary extensively in body size, from the feathertail possum, which has an adult weight merely of 10 to 15 g (0.35 to 0.53 oz) to the koala, which is considerably larger in southern Australia, weighing a mean of 8,500 to 12,000 g (18.7 to 26.5 lb). However, the powerful owl, while it has killed even adult koalas, only seldom takes the full-sized adults of the koala and even in some other mid-to-large prey species, such as the 1,700 to 4,100 g (3.7 to 9.0 lb) brushtail possums or the ringtail possums, of about half that weight, small and young individuals are typically (but not always) represented as the individuals caught. Only 15% of the ringtail possums caught in one food study were full-grown adults. The greater glider and the common ringtail possum (Pseudocheirus peregrinus), both weighing from 700 to 1,700 g (1.5 to 3.7 lb) in maturity, and the smaller sugar glider, weighing 80 to 170 g (2.8 to 6.0 oz), are the most prominent prey species in the powerful owl's diet in most regions. The significance of individual species in the diet is dictated by the local abundance of prey. The average estimated prey weight per one study was approximately 176 g (6.2 oz). However, another two studies stated the mean prey weight as 386.7 g (13.64 oz) and 323.2 g (11.40 oz). Not infrequently, prey weight averages between 50-100%, whereas in most other raptors, including large owls, there seems to be a "rule" that most prey weighs 20% or less of the raptors own weight. The mean weight of prey for powerful owls can be up to 10 times greater relative to their body weight than the mean prey weight of similarly sized northern owls, such as great grey or great horned owls.
  Not infrequently taken are the black (Pteropus alecto) and grey-headed flying foxes (Pteropus poliocephalus), the largest of Australian bats, although smaller bats have also been killed. Introduced mammals, namely rats (Rattus spp.), European hare (Lepus europaeus) and European rabbits (Oryctolagus cuniculus), especially the abundant young of the latter after their litters disperse, are also hunted. Opportunistic as are most predators and owls, given the chance the powerful owl will also prey on nocturnal birds such as the tawny frogmouth (Podargus strigoides). Roosting diurnal birds are also taken such as various cockatoos and parrots (around a dozen species thus far recorded), Australian brushturkey (Alectura lathami), dusky moorhen (Gallinula tenebrosa), white-faced herons (Egretta novaehollandiae), crested pigeon (Ocyphaps lophotes), wonga pigeon (Leucosarcia melanoleuca), kookaburras (Dacelo spp.), superb lyrebird (Menura novaehollandiae), olive-backed oriole (Oriolus sagittatus), Australian magpie (Gymnorhina tibicen), currawongs (Strepera spp.), honeyeaters (Meliphagidae) and crows and ravens (Corvus spp.). In one study, the most frequently killed bird prey species were pied currawong (Strepera graculina) and crimson rosella (Platycercus elegans) and avian prey taken as a whole was estimated to average 350 g (12 oz). Rarely, other birds of prey have been killed and eaten, including large accipiters such as brown goshawks (Accipiter fasciatus) and grey goshawks (Accipiter novaehollandiae). Insects may supplement the diet and are typically taken on the wing. Rarely, lizards and snakes are also captured.
  The vast majority of prey is taken from trees, often in or near the tree canopy, including unlikely items such as rock-wallabies (Petrogale spp.) that sometimes take refuge in trees. This species generally glides from perch to perch, watching for prey activity in surrounding trees until potential prey is detecte
caption: Powerful owl with its prey.
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