Hummingbird wings are amazing. They can flap dozens of times per second. And they can twist in ways that let hummingbirds fly upside down and backwards. But these wings also have one big limitation. They can’t bend as hummingbirds fly. That means hummingbirds shouldn’t be able to slip through gaps narrower than their wingspan. Yet somehow, they do.

Videos of Anna’s hummingbirds (Calypte anna) have now revealed how the tiny birds pull this off. The discovery “was a shocking revelation,” says Robert Dudley. He’s a physiologist at the University of California, Berkeley. He and his colleagues shared their findings November 9. The work appeared in Journal of Experimental Biology.

JoAnna Wendel