One less Redfin Perch
Australasian Darter flipping a Redfin Perch around to swallow it safely
Canon EOS R5 Mk II with a Canon RF 200-800mm F6.3-9 IS USM Lens [ISO 1600, 800mm, f/9 and 1/4000])
In mid October, I was photographing at the wonderful Jerrabomberra Wetlands, at the eastern end of Lake Burley Griffin. I was mainly trying to photograph flying birds, for a project that I am working on, when a disturbance in the water caught my eye. I had seen an Australasian Darter (Anhinga novaehollandiae) swimming around since I had arrived at the permanent hide that morning but hadn’t paid the bird much attention. Although, this time, I had noticed that it had been down longer than usual when it suddenly reappeared. Although it was swimming on the edge of the shadow from the hide, sometimes its head was nicely lit by the rising sun. I swung the camera down to have a look at it through the zoom lens and I noticed that it had a small, introduced Redfin Perch (Perca fluviatilis) speared on the end of its beak so I started clicking away. The wounds on the flank of the fish towards the front, visible in the photo, probably show that the darter speared it from the side in an ambush, not from behind while chasing it. The bird brought the feral perch to the surface to reposition it at the tip of its beak before it flicked it into the air, captured in the photograph, so that it could swallow the fish head first. Because birds don’t have teeth to allow them to grind the fish up, this is the safest way for birds to swallow a fish whole. Fish have spines in the fins and if a bird swallowed a fish tail first, the spines would likely puncture the throat of the bird, and probably leave the fish lodged in the bird’s throat. The thing that amazes me about this process is that somehow this bird has learnt to do this purely from observing its parents. The other alternative is that evolution has created an imprint of this process in the brain of the baby bird before it is born. Either way, I am always fascinated by how nature works.
