Bird Con
One of nature’s weirdest episodes plays out in this video — a bird mother feeding a parasite chick. The mom is a Red-winged Blackbird, one of the dozens that make the fennel forest in the northwest quadrant of the park their springtime nursery. The chick is a Brown-headed Cowbird. A cowbird female laid her egg in a blackbird nest and departed, leaving the blackbird mother to brood it and take care of it. The cowbird chick burst out of the egg first, before any of the blackbird babies. It may even have pecked their eggs and destroyed them, or pushed them out of the nest. It grows faster and begs for food more aggressively. The blackbird mom, like the females of numerous other species that cowbirds parasitize, doesn’t know the difference. She treats the parasite chick as her own and works hard to feed it, even though it’s already almost as large as she is, and can fly perfectly well — I watched it skillfully navigate up and over to a different bush after being fed. On the web you can see photos of tiny finch moms feeding cowbird chicks twice their size. No blackbird chicks were as developed yet as this cowbird chick in the video. The only good news is that there didn’t seem to be any other cowbird chicks in the nursery glen. This was a one-off. Still, it’s worrisome. The blackbirds aren’t on the edge of extinction, but their numbers aren’t as dense as they were a few years ago, or so it seems to me.
Around the Summer Solstice, the blackbirds generally gather their fledglings, pick up, and move on to parts unknown, to return — I hope in greater numbers — next season.
More about cowbirds: Wikipedia Cornell Audubon Previous posts here
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