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Powerful owl

Powerful owls

What are powerful owls?

Powerful owls are the largest nocturnal birds on the Australian continent. The scientific name for powerful owls is Ninox strenua. They can grow up to 70 centimetres tall with a wingspan of up to 140 centimetres. The larger male powerful owls can have a body mass of up to 2.2 kilograms. Powerful owls have a small head relative to their body size and have a rounded tail. They are grey brown above and off white below, with distinctive dark markings on their feathers. Their eyes are very large, yellow and set within a dark grey brown mask.

Powerful owl's legs have feathers and their yellow to orange feet are enormous with very large and powerful talons which they use to catch their prey. The sexes look similar but the female is generally smaller, with a narrower head. Juvenile birds are downy white on the head and under the body, they also have shorter tails than the adults. Powerful owls will often call to each other at dusk before they head off hunting for the night. Their call is a loud double-hoot with the second note slightly higher than the first. The deep call of the male can be heard over 2km away.

Where do powerful owls live?

Powerful owls inhabit the eucalypt forests, woodlands and sheltered gullies of south-eastern Australia. They are usually found on the eastern side of the Great Dividing Range from south-eastern Queensland through to South Australia. They need habitat with old growth trees with large hollows to nest.

What do powerful owls eat?

Like all Australian native owls, powerful owls are carnivores. They mainly eat medium to large tree-dwelling mammals such as possums and gliders. These owls will also  take roosting birds and sometimes small ground-dwelling mammals such as rabbits and small marsupials. They forage mainly in trees, swooping down on prey and taking prey with their feet whilst in flight. Their favourite food appears to be the common ringtail possum. Powerful owls can sometimes be seen holding on to the previous night's catch whilst roosting for the day. In one bite, a powerful owl can eat a possum’s head, taking the remainder of the kill back to the roost to feed itself and it’s family. Scientists have found that one powerful owl may eat over 250 possums in a year.

Powerful owls swallow all of their prey, including fur, feathers and bones. Later they’ll regurgitate these parts up again in the form of a pellet. Scientists can investigate powerful owl pellets to monitor where they live and what they have been feeding on.   

How are powerful owls adapted to their environment?

Powerful owls, like most owls, are nocturnal - that is, they are active at night. They have developed adaptations that allow them to sense, navigate and hunt in their forest habitat in the dark.

Powerful owls have large eyes set forward on their heads which allow great depth perception for hunting at night. They have excellent hearing to allow them to pinpoint exactly where prey is hiding or moving. They also possess very large and strong feet and talons that allow them to grab their prey whilst in flight. 

Powerful owls have special fringed wing feathers that allow them to fly and approach their prey completely silently.

How do powerful owls reproduce?

Powerful owls mate for life (over 30 years in some cases) and pairs defend their territory year-round. Powerful owls breed in the winter, mainly in May and June. Their breeding territory is large, usually greater than 1000 hectares in size. 

The male prepares the nest, which is usually a large hollow above 10 metres high in an old growth tree, and provides the female and young with food during the early part of the nesting period.

The female powerful owl most often lays two dull white, oval shaped eggs. The eggs hatch within 36 to 38 days. The female sits on the eggs and rears the young, coming out of the hollow later in the nesting period to assist in the hunt for food for the growing owlets. Young birds remain with their parents for several months after fledging and may stay within their parents' territory for over a year.

What threats do powerful owls face?

The powerful owl is listed as vulnerable on the schedules of the NSW Threatened Species Conservation Act. The powerful owl's habitat is adversely affected by land clearing for farming or housing, forestry practices and intense bushfires. They can survive in fragmented habitats such as farms, remnant bushland or suburban areas. Sometimes they are hit and killed by cars.

Young birds can be killed by foxes, cats or dogs. For their breeding cycle powerful owls require large tree hollows in old growth trees. Often these trees are logged for their timber or cleared to make way for farming or housing estates. Providing artificial nesting sites in the form of timber nesting boxes may be beneficial to powerful owl populations.

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