TIL: These Birds Trick Others Into Raising Their Gigantic Kids | Today I Learned

[Music] Turns out there's lots of different birds that don't build nests at all. They only lay their eggs in other birds' nests. This behavior is called brood parasitism, and a trick is you have to make an egg that looks like all the other eggs. Otherwise, the mother bird will kick that egg out of her nest and just raise her young.

But if the egg looks exactly like all the other eggs, then she doesn't have any other option than to raise them all as if they were her own. If you don't have a nest, then you can invest a lot of your effort into producing eggs. Cowbirds, for example, are one of the most common brood parasites in the U.S. They can lay an egg every single day, like a chicken, and just put it in a nest here and there. They don't have anything to do with the raising of their offspring at all; they leave that entirely to the mother of the nest where they deposited the egg.

The trick with brood parasitism is the chick of the brood parasite will grow much faster than that of the chicks of the actual nest. It gets really big, and its adaptation is to kick even before it can open its eyes. It's kicking and just kicks the other eggs out. [Music] Even if the other chicks hatch and survive, it's way bigger, and its mouth is way bigger. So when mom comes to feed, she sees this giant target mouth of the brood parasite, and all her chicks are buried underneath.

But she doesn't know which one is which. In fact, sometimes the brood parasite chick is much, much bigger than the actual mama bird, so she just thinks she has kind of a freak for a kid and just goes with it, I guess. [Music]