At the WEPA 40^th Anniversary picnic in October 2022, we had a fascinating presentation from Jenny Zvolanek, the coordinator for the national Powerful Owl Project. The talk was made even more exciting by our proximity to the hunting grounds of this great urban predator in Flat Rock Gully (FRG) between Naremburn and Northbridge.  WEPA is concerned that the proposal to work on a dive site at the top of FRG will disturb these wonderful birds and has lobbied hard, for this and a range of other reasons, to halt the planned Beaches Link tunnel project.  

The following information about these feathery urban icons is extracted from Jenny’s talk and supplemented with further information she provided after the event.

 Powerful Owls in Willoughby LGA
The Willoughby LGA is currently home to at least five breeding pairs of Powerful Owl. Between them, they successfully fledged six owlets in 2022, although sadly, one of these owlets passed away shortly after fledging. Powerful Owls are known in a further six locations in the LGA however the status of the owls in these locations is unclear.

A new breeding pair of Powerful Owls was located in Flat Rock Gully in 2021 after members of the public reported seeing cat remains that were consistent with prey remains left by a Powerful Owl. When discovered, the family had 2 beautiful, fluffy, fledged (already left the nesting hollow) owlets. There doesn’t appear to have been any breeding in this territory this year.

[Editor: the good news is that in January 2023 a pair was sighted in Flat Rock Gully by a local resident, later confirmed by the Powerful Owl Project.  Here’s hoping for owlets who call Flat Rock Gully home in 2023!].

Breeding
Powerful Owls breed in very large hollows (approx. 50cm x 50cm minimum internally) in very large old trees. The trees may be alive or dead. In Sydney these trees are most often Sydney Red Gum (Angophora costata), Blackbutt (Eucalyptus pilularis) or Sydney Peppermint (Eucalyptus piperita)

From about the beginning of March, the owls become more vocal as they cement pair bonds and announce the territory boundaries. During this time, they are also selecting the nest tree they will use that year. They will often return to the same tree to breed for many years, however, they are very sensitive to disturbance near prospective trees in the earlier part of the breeding season. In Sydney the female enters the chosen hollow to lay eggs, usually two, sometime around the middle of May to the middle of June, and will stay in the hollow, except to leave for very short periods, until the owlets are about 4 weeks old. During this time, the male roosts near the hollow, and does all the hunting for the family. From egg laying to fledge is approximately 13 weeks. The owlets will stay with the parents until around late summer/early autumn of the following year.

Hunting
Their main prey item in Sydney is possums, but they also eat flying foxes, gliders, birds, rats, rabbits, beetles and the occasional cat.

They catch their prey using their feet, suitably equipped with huge talons, and then use their hooked beaks to tear it into smaller pieces to swallow. Some of the feathers or fur are usually removed first, and also the intestines. These are often found on the ground below branches where the owl has been perched after catching the prey. Larger prey items, such as large brushtail possums, are sometimes partially consumed on the ground, presumably to reduce the weight before flying off with the remainder.

Please Do Not Disturb!
The Powerful Owls in Flat Rock gully are being monitored by volunteer citizen scientists from the Powerful Owl Project. The Project volunteers are specially trained in how to monitor the owls without disturbing them. As Powerful Owls are very sensitive to disturbance, extra efforts by members of the public to locate and monitor the owls are not advised.

If you come across a Powerful Owl while out walking, please do let us know where and when you saw it and what it was doing. Observe from a distance, stay only briefly, and be guided by the owl’s behaviour. The lower the owl is perched, the further back you need to be. If you observe any of the following behaviours you’re too close and need to move back or move on: the owl is wide-eyed and staring at you; it sits up very tall on its perch with the feathers on its head flattened down so the head looks very small; looks around, leans forward, poos; has one foot lifted and clenched with the talons displayed and facing you; drops its prey; an owlet trills during the day while you are watching it.

Please do not publicly share the location of the owl. Locations that become known lead to over-visitation, undue stress on the owls, and, often, abandonment of the location.

If you would like to help the Powerful Owls in your area, consider some of the following:

• support the local possum population by planting food and shelter species of trees and shrubs in your backyard. Try to achieve a continuous corridor of tall vegetation (ringtail possums don’t like to come to ground)
• install nest boxes for possums
• avoid using Second Generation Anticoagulant Rodenticides as these poisons cause secondary poisoning of non-target native species (follow this link for more information)
• avoid using flash photography on nocturnal birds, even during the day
• keep your dog on a leash when walking through bushland areas
• keep your cat contained within your property
• let your local council, and local State and Federal representatives of political parties know that you value the preservation of wildlife and their habitat
• support conservation groups that campaign to protect wildlife and habitat
• if you see a Powerful Owl, even if it’s a dead one, contact us at powerfulowl@birdlife.org.au

Characteristics and location

• The Powerful Owl is Australia’s largest owl, around 60cm from head to end of tail with a wingspan of around 140 – 150cm
• An adult male weighs around 1.5kg, the female is a little smaller and owlets are around 1kg at fledge.
• They have brown v-shaped chevrons on their fronts. Big yellow-orange feet with huge talons, and big yellow-orange eyes.
• Owlets are fluffy and white on their fronts and heads and stripy grey-brown and white on their backs.
• The call that people most often hear adult Powerful Owls make is a double hoot, and the owlets make a sound called trilling, which is a high-pitched sound that sounds nothing like the adult call and is often mistaken for a really loud insect by people who’ve never come across it before.
• In Sydney, they’re usually found living in gullies along creeklines in remnant patches of bushland, but we do know of a few pairs that breed in other places such as suburban backyards or schools.
• They breed in large hollows in very large, old trees, most often eucalypt species. It takes 150 years or more for trees to grow large enough to form a hollow big enough for Powerful Owls to breed in and some of the trees they breed in are estimated to be 300 or 400 years old.
• Their main prey item in Sydney is possums, but they also eat gliders, flying foxes, birds, rats, rabbits, beetles and the occasional cat. They come up into the suburbs to hunt, as well as hunting in bushland.
• Powerful Owls are thought to live for approximately 25 years.

Powerful Owl Project

• The Powerful Owl Project is the threatened species project of BirdLife Australia’s Urban Birds Conservation Program. The Powerful Owl serves as a flagship species to help raise awareness of the need to conserve habitat for wildlife in the urban environment and to engage the general public in conservation activities.
• We’re a citizen science project that’s been running for almost eleven years.
• We have a wonderful group of citizen scientist volunteers who monitor Powerful Owl territories and record their observations. Since the start of the program, around 700 volunteers have been involved.
• From their observations, we’ve learned where Powerful Owls live and breed, what makes good Powerful Owl habitat, how successfully they’re breeding, what they like to eat in the urban space, and the threats to their survival in the urban space.
• One of the things the information is used for is to work with Land managers such as local councils, NPWS, Ausgrid and Sydney Water to protect Powerful Owls and advise them how they can conduct their land management activities in a way that minimises the impact on the owls.
• There are more than 300 other native species that are hollow-dependent. By protecting the habitat needed for the Powerful Owls, we’re also protecting it for all the other living things in that space.