Collared sparrowhawk with prey
The crowd of noisy miners squabbling right outside my window had me jumping straight out of bed and reaching for my camera. More than the usual disputes for territory with the “house” little wattlebirds, this had the distinct vibe of a predator in action. And sure enough there was one of our collared sparrowhawks, perched on a low branch less than 5 metres from my front door, wrapping its laughing gear around what looked like one of the miners. They weren’t taking the dismemberment of one of their own lying down. The sparrowhawk stayed very very still while a crowd of miners scolded and divebombed it. But eventually it was time to do some butchery.
After a certain amount of viscera had been hurled around, the miners obviously decided that Bob wasn’t looking likely to rejoin the flock. While I was watching, one hold-out had a final swoop – the sparrowhawk ducked and called out repeatedly for moral support.
Calling for moral support
I’m not sure if it was the male (smaller, more bomb-able) or the female (generally chattier) calling for help. Male and female sparrowhawks really similar, even though when you see them side by side the females are distinctly larger.
Sparrowhawk pair
No chance of comparing sizes on this occasions – calls for help were completely ignored. Eventually this most belligerent miner of the group wandered off to harass some less aggressive passers-by.
I’ve been a vegetarian for over thirty years but this kind of gory scene doesn’t bother me one little bit.
Sparrowhawk with prey
Especially when it’s a noisy miner biting the dust. I had a look in my files to see if I had any good pictures of miners but nada. I’m not even that keen on their cousins the more elusive bellbirds – despite the atmospheric calls, like their cousins they’re colonial, driving other bird species out of their patch. Groups of bell miners can even, somehow, execute the trees they inhabit.
I’ve been a bit surprised at the distaste of lots of bird lovers for scenes of raptor butchery, when I’ve definitely smelt the smoke of barbecues drifting from their backyards. Where’s the solidarity with other top predators? Plenty of people seem to be fond of cats.
Thinning out the noisy miners is not the only environmental service provided by the local birdlife. The wattlebirds make short work of the window spiders, hovering like hummingbirds and plucking them from the tangled webs, that according to my kids, “make it look like Halloween at our place the whole year round”. The chooks clean up ticks and fruit fly larvae. And I captured a juvenile satin bowerbird earlier in the year making a dent in the local caterpillar population, with the help of mum.
I don’t mind when the bowerbirds do some tip pruning on my liquidambar tree.
But I’m a bit less keen on the scarlet blooms of my “running postman“, few and far between, getting munched, even if that means the local bowerbirds are subscribing, like me, to a plant based diet
Because they’re so famous for their decorative skills, whenever you see male satin bowerbirds collecting pretty stuff, you expect them to be thinking about their bowers. Like this visitor who I’m pretty sure was sussing out the “bowerbird blue” backyard tennis pole.
But I’m pretty confident that the Kennedia rubicuns flowers this bowerbird was collecting were for snacks, not for interior decor. How do I know? Well, some researchers got satin bowerbirds to choose their favourite colour of Froot Loop. Turns out, even though bowerbirds prefer blue and violet things as decorations in their love-shacks, given a choice of Froot Loop for a snack (not something that happens a lot, admittedly), they’d rather eat red and yellow ones.
Why, you might ask, were scientists trying to goad satin bowerbirds into eating Froot Loops? Well, it was all about the evolution of preferences for a blue-hued bower. Researchers were testing whether male bowerbirds evolved to decorate their bowerbirds with blue things because female bowerbirds liked blue snacks (Borgia 1987). Presumably they came up with this idea in a study with rump steaks, potato wedges and steamed broccoli framed and hung on the walls.
These researchers already had a pretty good idea that they wouldn’t find red Froot Loops in bowers – I know this because of a series of experiments that seem to me to essentially be an interspecies wind-up. One of these tests involved goading male birds by trashing one half of their bowers and seeing what would happen. Another, capitalising the “intense dislike for red objects at their bowers”, involved “a clear container over three red objects and quantif[ying]the time for each male to remove the container” and “super-glue[ing] a red square tile to a long screw and fix[ing] the tile into the bower platform and ground below so that it could not be physically removed” (Keagey 2011 1064). They also recorded the male bower-birds’ come-on lines – their mimicry of other birds – and spied on them to see if they got lucky. I don’t want to perpetuate any stereotypes, but is it a coincidence that the guy running this lab sports the name “Borgia”?
Turns out being smart improves your chances of getting lucky (if you’re a male satin bowerbird, anyway) but being very worried about red things in your bower not so much. Also, bowerbirds are capable of making a clear distinction between decorative items and food.
Somehow this doesn’t seem so odd to me. It’s humans, it seems to me, who don’t seem to be able to adequately categorise their Froot Loops.
References
Jason Keagy, Jean-François Savard, Gerald Borgia (2011) “Complex relationship between multiple measures of cognitive ability and male mating success in satin bowerbirds, Ptilonorhynchus violaceus” Animal Behaviour 81 1063-1070
Gerald Borgia, Ingrid M. Kaatz & Richard Condit (1987) “Flower choice and bower decoration in the satin bowerbird
Ptilonorhynchus violaceus: a test of hypotheses for the evolution of male display” Animal Behaviour, 35, 1129 1139
Matthew Mo (2016) “Diet of the Satin Bowerbird Ptilonorhynchus violaceus in the Illawarra Region, New South Wales, Australia” Corella 40(2)
More stories about the sparrowhawks in our backyard
Loves and leaves: our sparrowhawks do some nestbuilding
And more about our bowerbirds
Gymnastic bees, virgin fruit and the birds that ate spring
