Thursday, 18 April 2019

Southern Boobook preying on a micro bat

While looking for Spotted-tailed Quolls on Mt Elizabeth (1) last night, without success (2), we flushed a Southern Boobook that flew to a tree above the road giving us good views of the bird. It soon became apparent that the bird had a prey item. At the first brief glimpse of the prey it looked to be a dark fury animal so I assumed it was a mouse or a small marsupial such as an Antechinus species. However, after the Boobook devoured the first few portions ripped from the body of the prey, it then proceeded to swallow what remained whole, at which point to my surprise it became obvious that the prey was a micro bat.

Until seeing the Boobook feeding on a micro bat it had never occurred to me that they would be capable of capturing micro bats. Taking a micro bat on the wing would be a challenge for a Boobook, though I guess possible, however taking the bat while at rest would be more likely.

The following photos are in sequence and show the Boobook dining on a micro bat.

Please click on photos to enlarge.

My first photo of the Boobook – in hindsight looking at the photo the prey item can just be made out under the bend in the branch below the Boobook.
Our first view of the prey – what is it?
The Boobook did not appear to be concerned by our presence and our light – it was preoccupied with its meal.
Knowing the prey is a micro bat in this photo the head and ear or ears may be visible.
The Boobook stopped briefly to look at the light before continuing with its meal.

When I took this photo it was clear to me the prey was a micro bat.
In this photo the bat’s leg with small claws is just visible.
While this photo is blurry due to the slow camera speed (ISO 8000 and 1/200 second shutter speed) it is included because it shows the moment the Boobook commenced to swallow the remains of the bat whole. The Boobooks body shook vigorously with the swallowing effort.

At this point it looked like the bat was gone - however it took more effort to get it down.

This photo shows the Boobook using a foot to manipulate the bat in its mouth to assist with swallowing.
Four seconds later in this photo the bat has been swallowed.
One micro bat meal completed. A moment later the Boobook moved to another perch just beyond the light and we moved on.

Based on the times recorded on the photo files it took the Boobook 1 minute and 36 seconds to consume the bat.

Our experience last night once again shows that when you spend time in nature you never know what might turn up and what you may learn – I now know Boobooks prey on micro bats – given they are both nocturnal species I guess this is not surprising. While Boobooks will take some larger insects (Eg moths) the micro bats can harvest a large range of insects and convert these to protein for the Boobooks – just a small part of the web of life in the Mt Elizabeth Mountain Ash forest.

(1)  Mt Elizabeth is 934 metres high and is to the East of Tambo Crossing in East Gippsland. A 5,234 hectare conservation reserve at the top of the mountain is managed by Parks Victoria. The mountain is a caldera and an outlier of the Snowy River Volcanics.  The reserve is dominated by Mountain Ash.
(2)  On a recent day time trip to Mt Elizabeth a now rare Spotted-tailed Quoll ran across the road in front of our vehicle so I had returned at night to see if we could find more Quolls. No quolls were seen. The night was warm with wind and a near full moon so conditions may not have been favourable. I will try again soon on a cold, still and dark night.