Comment of the Day: Cowbird Edition

Illustration for article titled Comment of the Day: Cowbird Edition

Today's comment of the day comes directly from a bird's worst nightmare. In response to today's post on the nesting habits of brood parasite, the cuckoo finch, commenter Aloicious shares this even darker tale on the habits of another brood parasite, the Cowbird:

When a Cowbird parasitizes a nest, it'll pierce one egg and taste the contents to figure out at what stage the egg is at. If it's a young egg (ensuring the Cowbird chick will hatch at the same time or before the other chicks), the Cowbird will lay an egg in the nest. If the egg is old (the Cowbird egg would likely not hatch), the Cowbird will destroy as many eggs as possible in that nest, hoping to force the hosts to renest. The hypothesis is that by doing this, the Cowbird will force more nests to be the correct age for parasitism.

Very cool.

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Cowbirds: Just one more reason why ornithophobia is the most reasonable of all phobias.

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DISCUSSION

Yeah, but the cool thing about them is that the behavior is the evolutionary answer to how cowbirds could be nomadic, following buffalo herds, and still assure that their genes are passed on to another generation. That is, the host nest raises the next generation for the parents, freeing them up to follow the producers of a major food source. Cowbirds ate (back when there were large herds of buffalo) the seeds and small insects stirred up with the movement of large herds and trapped in the buffalo's coat.