How do our possum assassins use urban landscapes?

the eyes of a possum assassin

An urban living possum assassin (AKA powerful owl).

We are incredibly lucky to have a native apex predator haunting our urban landscapes.  The powerful owl (Ninox strenua) is known to live in restricted areas of Melbourne, Sydney and Brisbane. They silently travel around dropping in on unsuspecting possums and gliders, and feasting on them.  It is not uncommon to encounter an owl with the decapitated corpse of a possum in its talons.

Enough with the gore! What do we know about these amazing predators in our urban environments?  We know they are not very common in urban environments, and large areas of our cities are completely unsuitable for them due to loss of vegetation associated with urbanisation (Click here to check out some models of habitat for powerful owls in Melbourne).  We also know there is plenty of food for them in our cities, but their capacity to breed is probably limited by a lack of large tree hollows (Another paper that may interest you on urban ecological traps for powerful owls).

Ok, so what don’t we know?  Well we really don’t know too much about how powerful owls use the urban landscape. How far do they travel? Do they go deep into the suburbs or do they stay in the more wooded parks? How much space does an owl actually need to survive in a city? How can we better manage our urban landscapes to facilitate the expansion of powerful owl populations? Hence our new research project to track urban powerful owls in Melbourne.  This research is part of our Deakin honours student’s (Nick’s) project. A parallel project will be aiming to do the same thing in Sydney, so we can compare and contrast two different cities.

So last night was our first night of trying to catch a powerful owl to put on a GPS logging device and attached radio transmitter. I will say it is not easy to catch owls, and we have done it a fair bit so have a few little tricks we have learned along the way.  As luck would happen we caught one! First attempt! There is no way we will be maintaining that average!

A happy honours student

Deakin honours student Nick with the first powerful owl of his research project. I think he looks kind of happy.

Imagine sitting in the dark, nets up in the canopy, knowing there is an owl close by. It is exciting, and scary at the same time.  The owl never called, it just quietly cruised around where we were. So last night the owl came into the net.  We were lucky, and this launched us into a flurry of activity and fitting of trackers etc.

How do you attach a tracking device to an owl? We used a tail mounting approach, where the device is fixed to the two central tail feathers. It is a useful approach as the tail feathers will eventually naturally moult and the device will fall off the animal.  Also, the device sits very nicely to not impede its flight. Finally, the feathers of the back and wings cover the device up so you cant see it.

Tail mounted transmitter

The GPS/radio tracking device fitted to the tail feathers of our powerful owl.  Note: all the other tail and back feathers are being held out of the way to show it to you.

So after fitting our tracker to the owl, we gave it a final check to make sure both the owl and the device were fine.  Nick held the owl up in the air, and whoosh, it was gone.  It flew really well up to a nearby tree. I might of imagined it, but I am sure it gave us a dirty look before heading off through the trees.

Nick releasing powerful owl

And Whoosh off it goes! Nick releasing the first powerful owl carrying a GPS tracker.

Powerful owl after release

The owl just after release perching briefly on a branch.  Note you can just see the tip of the aerial at the end of the tail, and the tracker is held nicely under the feathers.

We checked the owl a couple of times last night and again this morning.  It is doing really well.  This morning it was roosting with another adult powerful owl some 500 metres away from where we caught it.  The GPS recording where it goes when we are not watching it.  Technology has come a long way, and with every technological advance comes opportunities for us to understand our wildlife better. This owl may be able to help us design urban landscapes better to suit the needs of our wildlife.

Me with a powerful owl

Me with the owl. It really doesn’t look all that big, but this owl was just over 1.5 kg!

2 thoughts on “How do our possum assassins use urban landscapes?

  1. really great, gps technology is really coming along in leaps and bounds yielding fantastic results. This project will undoubtedly provide vital data for analysing the importance of varying urban habitats for powerful owls!

    Liked by 1 person

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