Cowbird

The ‘chipping sparrows feeding a cowbird chick’ phenomenon, which I hoped to see this year in the Arboretum, actually happened much closer to home: on our deck. I knew there was a chipping sparrow nest in the forsythia hedge, but I hadn’t realized the cowbirds had found it. And then one day there it was, a single cowbird chick, sitting on our deck rail, begging….and the tiny chipping sparrows flying back and forth to the feeder, bringing it seed.

How hard the chippies worked! Cowbird was never satisfied, begging and begging, its yellow gape open and its wings quivering. And the chipping sparrows, genetically programmed to feed that gaping yellow beak, kept feeding it.

cowbird-chick-begging-4

Photo courtesy of  https://bybio.wordpress.com/tag/chipping-sparrow/ (a marvellous blog…check it out!)

Then it learned to fly, so instead of sitting on the deck rail, it sat on a feeder rung, the food an inch or less from its beak – and begged. And was fed. This went on for about a week…and then one day, it sat there, and begged, and no-one came. It sat, and waited….and watched as young red-winged blackbirds found food, and ill-kempt, blurry chickadee fledglings found food. Still it waited. Occasionally it hopped down to the ground; occasionally the chipping sparrows came by to feed themselves.

After a day it tried the feeder, clumsily and not terribly successfully, not appearing to work out how to balance and feed at the same time. And then the grackles came, with their begging fledglings, and after a day of disappearing food and noise and little birds chased away, we took the feeders down. (They’ll go back up in a while, after the grackles have moved on somewhere else.) But poor Cowbird! It sat, disconsolate, for much of the day. Other birds came, looked at where the feeder had been, left, knowing full well there are many other feeders in the neighbourhood. Cowbird, however, wasn’t bright enough (or programmed genetically) to follow them, at least not at first.

I wonder when cowbirds know they are cowbirds? They don’t imprint on their host parents: our cowbird doesn’t think its a chipping sparrow, or it would never leave, flock with other cowbirds, find a cowbird mate. But for its first weeks, it expects to be fed by chipping sparrows, begs from chipping sparrows, ‘relates to’ chipping sparrows. What happens in the cowbird brain to assert its true identity?

Cowbird has gone. Its foster parents are still hanging around our garden, finding wild food, roosting in our trees. (One tried to fly in my study window this morning.) They may well breed again, and might actually raise some chipping sparrow chicks this time. And if Cowbird was a female, she’ll lay her eggs, if she survives to adulthood to do so, in chipping sparrow nests, because in some tiny bit of her brain, she knows that’s who raised her.

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