Chris Watson

central australia

Owlet-nightjar ant-eating behaviour

Birding, Tourism, ResearchChris Watson

Australian Owlet-nightjar Aegotheles cristatus, basking in daylight at a roost hollow. Front-facing eyes, super cryptic, super creepy and, apparently, prodigious ant-eaters.

Recently, I had an interesting encounter on a photographic tour I was leading in Central Australia.

I’ve read about the foraging tactics and diet of Australian Owlet-nightjar Aegotheles cristatus, before, most memorably in the work of Dr Lisa Doucette. An article Dr Doucette wrote in The Bird Observer back in Feb 2011, really stuck in my mind. In that piece, she detailed the differences in the dietary composition between birds studied in the semi-arid ranges of Central Australia and the wet eucalypt woodland of NSW’s Northern Tablelands.

The bit that really stuck with me was the following paragraph elaborating on the fact that the largest portion of the desert birds’ diet (31% by volume) comprised… ants.

“Catching ants, an abundant, reliable taxa, active even at sub-zero temperatures, would require less energy and time to obtain.

Flightless worker ants that primarily forage and nest on the ground were the dominant prey type in the Australian Owlet-nightjar’s diet overall. This strongly indicates that the Owlet-nightjars are foraging on the ground following trails of ants and exploiting nests, not simply using a “perch-and-pounce” approach to capture large terrestrial prey. Relative to other species of nightjar, owlet-nightjars have longer legs, making them far more agile on the ground and better enabling them to exploit terrestrial prey.” - Dr Lisa Doucette, Foraging tactics of the Australian Owlet-nightjar, THE BIRD OBSERVER, No. 868, Feb 2011, p.6-8.

This astonished me for two reasons primarily: I’d never thought of Owlet-nightjars as being even remotely long-legged and; ants seemed an unlikely prey item for an animal equipped with a beak that appears best adapted for catching airborne prey. (Now, looking at my photo of the beastie above, I should have been more observant - it clearly has a decent set of pins.)

It was illuminating.

I never thought I’d witness this curious behaviour, not least because even in Central Australia where the birds are incredibly common, despite hearing them on most nights out in the scrub, I didn’t see them very often at all. The mental image of an Owlet-nightjar perched on the ground over a line of ants like some weird gigantic feathered Thorny Devil was incongruous. But it happened.

The more-famous Central Australia ant-eater, the Thorny Devil, Moloch horridus.

Wandering up the path from Ellery Creek Big Hole to the car park on a warm evening in March, I was startled by the sight of an Owlet-nightjar on the edge of the path in front of me. It was surprised by my intrusion at first but I retreated slowly leaving it in the edge of the torch beam and it shortly turned away from me and continued what it was doing. What it was doing, was straddling a line of ants making their way along the edge of the concrete path and, literally, decimating them. It was repeatedly and frenetically pecking at the line of small black ants, gobbling down the hapless insects.

I’ve no reason to think that these observations are unique but still thought it worth documenting them here in case they are of any use or interest to anyone conducting further research on the species. Unfortunately, my camera was equipped with a fixed 50mm f1.2 lens for star photography so my captures of the encounter are disappointing to say the least. After a couple of almost worthless record shots I sprinted to the car for a zoom lens but was crushed to return and discover that the bird had flown.

Record shots = you *really* had to be there.

Still, it was a distinct privilege to sit with that bird for those few seconds and gain this firsthand insight into this surprising behaviour.

CBW

 

PS: I was leading this private photographic tour for Mark Carter Birding & Wildlife. We had numerous one-off wildlife encounters like this, and were able to perfect our star photography in a number of scenic locations over successive clear, dark nights. If this sort of thing is up your alley, you should get in touch with Mark and see this astonishing region with someone who knows it best. http://www.birdingandwildlife.com/

Your Deserts Need You

Birding, Tourism, ResearchChris Watson

Desert birding - this is the year

Lately I’ve been back in the desert. Sometime soon, you should head to the desert too. Whether you’ve never been before, or you’re a veteran Outback traveller, this year, as a birder, you ought to get out there.

My recent trip was the first of what will hopefully be a series of trips to collect data for a research degree I’m undertaking. This first one involved myself and my colleague in most desert escapades, Mark Carter, leaving Coolangatta and heading west with no itinerary other than reaching Alice Springs in ten days or so. The only mission was to fill in a few blanks on the desert map that neither of us had visited and to try and see what few lifers might be lurking there for us. Chief among these were a few species of grasswren.

There was a dual purpose for finding the grasswrens: neither of us had seen most of them and my research involves obtaining good quality audio recordings of Dusky Grasswrens across central Australia so any recording encounters with congeneric species would be useful practice.

The most obvious thing we noticed as we barrelled west of the divide and into the arid zone of the NSW/QLD border districts, was how much lying water was on the country. From the very first afternoon we drove through large thunderstorms. At Cunnamulla, roads to the north and west were all closed forcing us to head south and miss some of the best Grey Grasswren country out toward Innamincka. But we still made it to a flowing section of Cooper Creek where Mark was able to give his kayak its blooding on a proper desert river.

This is where Burke & Wills went wrong: they should have brought a kayak.

Heading south brought us into the range of the intriguing NSW race obscurior of Thick-billed Grasswren so all was not lost yet. This is not intended to be a comprehensive trip report so to cut a long and all-too-familiar story short: we dipped. Consecutive days over 40 degrees, a dearth of recent observations and inexperience recognising the bird’s habitat certainly contributed to our dip. These factors and the ever-present threat of being rained-in kept us moving southward after a fairly full day of gibber bashing.

The afternoon weather was regularly foreboding...

From Port Augusta the punishing temperatures eased but the rains continued. We had success with the Western Grasswren near Whyalla and found the birds in good voice and reasonably approachable for photographs and recordings despite quite a gusty day. The Thick-billed Grasswrens showed themselves ever-so-briefly further up the track near Coober Pedy and then we kept pushing north to Alice Springs and Dusky Grasswren country with a few days up my sleeve to make some more recordings.

The one constant of this trip was our (or at least my) inane commentary on the amount of water we were seeing. Most of the numerous bridges across the Stuart Highway between Coober Pedy and Alice Springs had water flowing under them and those that didn’t, recently had. The Palmer River was flowing strongly, the Finke crossing at Henbury was swollen as it had been for some weeks, and every clay pan and gravel pit was brimful. Every gibber plain from Tibooburra to Idracowra looks more like a golf green than the bleak Martian vista they usually resemble. Mobs of Emu were encountered the whole way through and, as evidenced by a juvenile bird even showing up on the beach at Shoalhaven Heads, Inland Dotterels have clearly bred very well across their range. These captivating little shorebirds were everywhere.

Emus on the 16th fairway near Tibooburra.

In all my years knocking about The Outback I’ve never seen it like this. Even the wet years of 2010-2011 didn’t manage to spread the pulse of life as far across the landscape as the last 6 months of wet weather in Central Australia have done.

Many of the roads across The Outback have only recently started to re-open after lengthy closures and many will need a fair amount of repair work done. The country will need to dry a bit and birds will continue to breed up but, by May, birding should be hotting up just as the weather is cooling down.

Ormiston Gorge at the moment: ringing with the chatter of breeding Budgerigars in every tree with the songs of Dusky Grasswrens cascading over the cliffs and hillsides.

Mark and I are heading off on another desert expedition in May. This time we're covering the Great Victoria Desert and parts west in search of a few birds that will be new to many birders’ lists: recent western splits like Naretha Bluebonnet and Copperback Quail-thrush are both high on the target list and we’ll be on constant look-out for other specialties in this region like Scarlet-chested Parrot, Sandhill Grasswren, flocks of wild Budgerigar, and Princess Parrot. Boom years like this don't come around too often and if nobody is out there to witness the spectacle of it all a great opportunity will have been missed. We aim to get out there during the peak of activity as birds are coming off multiple consecutive breeding cycles and the weather is at its most agreeable. We'll be seeking the above-mentioned bird species, but we'll also be looking to document and photograph all manner of fascinating and uncommonly encountered desert wildlife and flora before the inevitable drying, the burning, and the long wait for the next period of such frenzied productivity.

Sunset over Willochra Plain - hard to beat.

This 10 day expedition leaves Alice Springs on the 24th of May (all the details can be found over on Mark’s website here) and it'd be great to have you along. We only have a few seats left so don’t muck around – get in touch! We look forward to seeing you out there.

CBW