Bird of the month: Powerful Owl

Posted on 29 July, 2021 by Ivan

Welcome to our sevententh Bird of the month, a partnership between Connecting Country and BirdLife Castlemaine District. Each month we’re taking a close look at one special local bird species. We’re excited to join forces to deliver you a different bird each month, seasonally adjusted, and welcome suggestions from the community. We are lucky to have the talented and charismatic Jane Rusden from BirdLife Castlemaine District writing about our next bird of the month, with assistance and photos from the brilliant Damian Kelly.

Powerful Owl (Ninox strenua)

These guys are huge, Powerful Owls are enormous, amazing and BIG! However, for such a massive bird they can be extremely difficult to find, even when you know their location. My partner has excellent bird spotting eyes (that’s why he’s a ‘keeper’ and I really hope he doesn’t read this) and he describes them as looking like a dark basket ball very high in the canopy, in the biggest tree around. If you’re really lucky, have the patience and magic like Damian Kelly does, and a very long camera lens, you can see Powerful Owls as clearly as Damian’s stunning photos.

I tell you, Bird of the Month would be pathetic if it weren’t for Damian Kelly, but regular readers have probably guessed that.

Back to Powerful Owls and a closer look at their magnificence.

I’ve said they are big and they are in fact Australia’s largest owl, with a body length of 60cm and wingspans of 110cm to 140cm. It appears pairs mate for life and may be together for up to 30 years. Males are generally larger than females, she will do all the 35-38 days of egg sitting through winter, while the male feeds her. If you see a Powerful Owl through winter, it should be the male snoozing with the food he has hunted for the female, in his talons. Usually a possum such as a Ringtail, or Glider, as well as some bird species including cockatoos, ravens, magpies and choughs, which would have been snatched from their roost during the night. Looking at the species Powerful Owls eat, it’s evident they are all arboreal, in fact 95% arboreal. The remaining 5% is not preferred food and is made up of rabbits and larger insects when obtainable, like longicorn and scarab beetles. Pellets of partially digested bones and fur that are brought up can sometimes be found on the ground under roosts, along with whitewash, which is their poo.

Cryptic adult on the higher branch, and juvenile Powerful Owl with pale breast. Photo: Damian Kelly

Data shows Powerful Owl populations have fallen to around 30 breeding pairs in what remains of Box-Ironbark Forests, and they are listed as “threatened” as populations continue to struggle. Pressures include lack of large old trees with suitably sized hollows, as well as declines in arboreal mammal populations. Additionally, with a home range of 300ha to 1500ha, suitable habitat for these huge owls is not be easy to find. Having said that, they will roost in non-native trees as well as natives, and can be found in a variety of habitats from moister to dryer forests, but have also been found in urban areas of Melbourne and Sydney. Clearly an adaptable bird, but with limits, perhaps due to its large size.

As a note, the whereabouts of Powerful Owls is kept a bit of a secret, this is due to their rarity and susceptibility for disturbance by humans. If you wish to go looking for them, expect long hours in the cold and wet, a sore neck by the end of it and a high chance of failure, however rewards are huge if you manage to spot a Powerful Owl, and please make sure it is not disturbed in any way.

To listen to the Powerful Owl distinctive call and for more information about local Owls, see our previous blog here.