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 birds, they must survive a long stretch to independence in young owls after fledging.

It can be considered, along with its sister species the rufous owl (N. rufa), as Australia's analogue to the genus Bubo.

Unlike in a vast majority of owl species, the male is slightly larger than the female on average.

[8] Its body mass is about the same on average as the great horned owl (Bubo virginianus), but it has a proportionately much longer tail and wings than that species.

[9] In comparison to the barking owl (Ninox connivens), it is much larger and lacks that species' white-spotted smoky-brown colouration on the upperparts and dark grey to rusty streaks on a whitish background on the underside.

The habitat of the powerful owl is tall, humid forests ranging through to some drier woodlands in northern Victoria and the western slopes of New South Wales and Queensland.

Recent mapping work has shown that streams between ridges covered with Eucalyptus forest are often prime habitat for this species.

[3] They also occasionally range into plantations, mainly of pine or native tree species, and urban and rural parks and gardens.

They frequently roost during the day on branches in tall, open trees, often while still holding the prey caught the prior night.

[17] The most largely taken prey species in many regions are adults of common ringtail possum (Pseudocheirus peregrinus) which can weigh around 700 g (1.5 lb).

[12][13][18] Larger common brushtail possums (Trichosurus vulpecula) of all ages can be taken, but young specimens are preferred since they are abundant in spring and easier to catch than adults around 3,500 g (7.7 lb) in weight.

[13] On some occasions, they even take both young and adults of mountain brushtail possums (Trichosurus cunninghami) which can grow about 4,000 g (8.8 lb).

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.

One theory is that the male regularly holds onto the prey during the day, and thus can control the distribution of food to the family in keeping with his dominant size; whereas in most owls, females are larger and more dominant, and thus the male could not display such behaviour as keeping food from his larger mate.

However, some overlap in the diet was recorded between all three species, and a certain level of competition was predicted, in which the powerful owl would presumably be dominant.

Young powerful owls are mostly off-white with a greyish-brown mask and grey on the wings and coverts, and are obviously distinct from the adult plumage.

[3][4] Although practically no predators of this species exist, except in very rare, anecdotal instances, wedge-tailed eagles (Aquila rapax), and powerful owls have been recorded killing each other in territorial and breeding skirmishes.

Also, they are often victim to and occasionally even injured by heavy mobbing by larger passerines such as currawongs, magpies, and crows and ravens.

In one case, a pair of Australian ravens (Corvus coronoides) attacked and killed a powerful owl, likely to defend themselves and their nest.

[30] Powerful owls are not listed as threatened on the Australian Environment Protection and Biodiversity Conservation Act 1999.