Owlet-nightjar ant-eating behaviour
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/