Small bird, big trick: How a hummingbird chick acts like a caterpillar to survive

by Yvaine Ye, CU Boulder
March 17, 2025

When Jay Falk and Scott Taylor first saw the white-necked Jacobin hummingbird chick in Panama’s dense rainforest, the bird biologists didn’t know what they were looking at.

The day-old bird, smaller than a pinky finger, had brown fuzz all over its body. When Falk and Taylor walked closer to the nest, the chick began twitching and shaking its head—a behavior they had never seen in birds before.

It turns out the hummingbird might fend off predators by mimicking a poisonous caterpillar that lives in the same region. In a new paper published March 17 in Ecology, Taylor, associate professor in the Department of Ecology and Evolutionary Biology at CU Boulder, and his team described this unusual mimicry behavior for the first time in hummingbirds. 

“We know so little about what nesting birds do in the tropics,” said Falk, the paper’s first author and postdoctoral fellow in Taylor’s lab. “But if we put more effort into observing the natural world, we might discover these kinds of behavior are very common.”

Keep reading: https://www.colorado.edu/today/2025/03/17/small-bird-big-trick-how-hummingbird-chick-acts-caterpillar-survive

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecy.70060