Owl pictured devouring ringtail possum at Canberra park

Bird watchers from around the country are flocking to catch a glimpse of a large owl that has been spotted devouring ringtail possums and sulphur-crested cockatoos in a suburban Canberra Park.

The bird, a powerful owl, which is Australia's largest species of owl, has taken up long-term residence in Haig Park near the CBD, ABC News reports.

"It is classified as an apex predator, so what they will do is hunt a variety of food, mainly tree-dwelling mammals," said National Zoo and Aquarium senior keeper Brendan Sheean.

Canberra Ornithologists Group member Terry Bell was among the first to spot owl scats on some tarmac outside a bowling club in north Canberra and then locate the powerful owl in large oak trees at the nearby park.

He said the owl had been pictured with prey that included sugar gliders as well as other birds such as galahs and Canberra's emblem bird, the gang-gang cockatoo.

For months now, bird enthusiasts had been staking out the park, armed with tripods and binoculars, to see a species of bird whose populations are in decline across NSW.

Mr Sheean said the owl, which is classified as vulnerable, may have moved to the park looking for a mate or new territory.

He said once partnered, powerful owls could breed for 30 years.