Wednesday, May 1, 2013

Holy Shit, Brood Parasites!

Brown-headed Cowbird

I was out in my backyard the other day when I heard an unfamiliar birdsong. Not a particularly rare one, but one I hadn't heard in my backyard before. It was this li'l fella:



I had to know what it was. Luckily, I got a good glimpse of him, and if you google "black bird with a brown head" he's the first three hundred results. Meet the conveniently named Brown-headed Cowbird, one of the biggest assholes of the avian world.

You see, the Brown-headed Cowbird is what ornithologists refer to as a brood parasite. Brood parasites are a bunch of lazy sons of bitches who can't be bothered to raise their own children. Instead, they lay their eggs in other species' nests. Like Phoebes.

Eastern Phoebe
She's lost a lot of weight since Friends

Imagine you're a pleasant little Eastern Phoebe, off hunting some insects or extra insulation for your freshly laid eggs. When you come back to your nest, you see that some nefarious Cowbird has surreptitiously placed her blatantly non-Phoebe egg in your very much Phoebe nest.
Phoebe nest with Cowbird egg
It's like they're not even trying to be subtle. (Spoiler Alert: They aren't)

You decide that enough is enough. You'll tolerate sharing the bird feeder with other species, but this is just insufferable. You nudge the damn thing over the edge of the nest and let it fall.

You've just made a terrible mistake. That's the avian equivalent of trying to abduct Michael Coreleone's children, and I mean that as literally as you can possibly mean a comparison between a Pacino character and a mid-sized bird.

What Cowbirds do in response is gleefully referred to as "mafia behavior." If a bird disposes of their free-as-in-kittens-not-as-in-beer eggs, the Cowbird will return to the nest and wreck the everloving shit out of it in furious vengeance.
Brown-headed Cowbird Courtship
It's a courtship dance, but I choose to think of it as him making an offer she can't refuse.
 
This behavior has been around for so long that smaller birds have adapted to it. Most of the time, if a Phoebe sees a suspicious egg in its nest, it'll gulp heavily and go about its business, raising the new chick as its own. Even though that often means the Phoebe's own offspring will be casually murdered by the much bigger and more demanding mafia bird baby.

All this comes down to one delightfully terrifying thought: Birds run protection rackets.

Holy shit.

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