Powerful Owl - Calling All Light Sleepers

Written by Simon Mustoe



About this time of year, you could be woken at night by the double-hoot of one of Australia's owls. If you live in the suburbs (or even CBD) of Sydney, Melbourne or even Brisbane, there's every chance one of the world's largest owls, a Powerful Owl, is calling from your back yard.

So over this summer, keep your ears open if you sleep lightly and maybe you'll hear the soft calls of our largest owl as it silently hunts through your back garden. 

 

ARE YOU A LIGHT SLEEPER?

If it's the middle of the night and you wake to a sound outside, try listening a little more. Sometimes the faint call of an owl might break the silence and with these simple rules, you can work out which one:  

If the sound you hear goes DOWN in pitch, something like this: http://www.xeno-canto.org/389950 then it's a Southern Boobook. 

However, the much deeper call of Powerful Owl goes UP in pitch, like this: http://www.xeno-canto.org/species/Ninox-strenua

 

OUR URBAN OWLS

In Melbourne, Deakin University scientists have been using GPS technology to monitor how Powerful Owls make use our urban landscape.

The study was part of student Nick Bradsworth’s ambitious honours project with six Powerful Owls fitted with a radio transmitter and GPS logger, taking readings every 20 minutes. Preliminary data showed the owls covering areas of around four square kilometres over 12 nights. 

Powerful Owls traditionally occupy home ranges of between 400-4,000ha so finding them occurring over 4 square kilometres is equivalent to the lower-end of their natural range - maybe this stands to reason, as possum population density can often be much higher in towns. 

The question Bradsworth's study was trying to answer was, how much time do they spend using suburban backyards and other urban areas. This is critical to developing better urban planning guidelines for the conservation and enhancement of urban Powerful Owl populations - since this is a bird endangered by forestry, even in our National Parks, that have been heavily logged in the past and still have few trees mature-enough for them to nest.

Mr Bradsworth said keeping a watch on owls had been an ongoing interest.

“I have always been particularly fond of owls and in recent years, whilst I have been studying my undergrad, I have been lucky enough to monitor a breeding pair of powerful owls in a local reserve,” he said.

“I have spent countless numbers of nights watching and following this pair, waiting for their chicks to leave the nest, and watching the chicks take their first (clumsy) flight from the hollow.

 

HABITAT HOLLOW CARVING

One way to preserve Powerful Owl habitat, is to use artificial hollows. The team from Melbourne Tree Care use an innovative approach. Rather than waiting 150 years for hollows to rot out naturally, they will carve out hollows big enough for native wildlife to use immediately. In this film they show how it's done.  

Powerful Owls make a living eating possums, so anyone with fruit trees or a vegetable patch, should be delighted to have them in the vicinity. Breeding habitat is in huge tree holes, which in urban areas, are still quite rare.

So it's encouraging to see companies applying simple ecology to preserve our natural heritage. It goes to show, sometimes something quite easy and almost cost-free is all that's needed to make a difference.  

THE POWERFUL OWL PROJECT

If you'd like to find out more or contribute sightings of Powerful Owl, head to BirdLife Australia's project page:

http://birdlife.org.au/projects/powerful-owl-project

To follow the stories and photographs of Australia’s urban Powerful Owls on Twitter, check out https://twitter.com/UrbanPowerfuls

Wildiaries •