We know that caterpillars are masters of mimicry — they pretend to be snakes, leaves, twigs and even bird droppings. It's understandable that such vulnerable critters would adapt to their surroundings to avoid being eaten. But did you know there is a bird that mimics a caterpillar for the same reason? 

As an adult, the cinereous mourner, Laniocera hypopyrra, is a nondescript drab gray bird of the Amazon. However, during its time in the nest, it looks more like a caterpillar than a bird. That's because the chicks have adapted a strange defense mechanism — not just to look like a toxic caterpillar, but to move like one too. 
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Cinereous mourner bird on leaves looks like a caterpillar

Photo: Santiago David-Rivera

From afar, it's hard to tell whether the cinereous mourner nestling is a bird at all, and that's a good thing. In the Amazon, chicks are weak, providing an easy snack for all kinds of predators. If there's one thing we've learned about the animal kingdom, it's that orange is a warning color. The chick is a fluffball, a mixture of soft and spiky feathers with black spots and white hairs all around. A peculiar and jarring appearance, to be sure. But now researchers have found toxic caterpillars of the Podalia or Megalopyge family nearby that are similar in appearance, from the orange coloration to the white "hairs," and they are about the same size.

It is the first recorded example of birds mimicking the appearance of other species to avoid predation. The chick keeps its vibrant plumage for the critical first 18-20 days of its life until it can escape predators on its own.

Oddest of all, the cinereous mourner actually wriggles around in its nest — in much the same way a caterpillar would — until mama bird comes by with a snack. Check out the video below for a fascinating look:

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Anna Norris is an associate editor at Mother Nature Network. Follow her on Twitter and Google+.

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