See how hummingbirds sneak through small spaces

The tiny birds have a few techniques to fly through tight gaps

A red-headed hummingbird hovers in the air in front of blurred foliage

Hummingbirds — like this male Anna’s hummingbird — can’t easily bend their wings. This makes it difficult for them to fly through gaps smaller than their wingspan.

Nicholas Chesarino

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.

Image: The words “Wild Things: A Graphic Tale” are written in green block letters. A toucan perches on the W in ‘Wild,’ a jaguar sleeps atop the T in ‘things,’ the letter S in ‘things’ is a snake, and other animals surround the text.
How hummingbirds flutter through small spaces. Written by Maria Temming. Illustrated by JoAnna Wendel. Image: A hummingbird with a magenta head, white body and some green on its wings and tail flies past a field of purple lavender flowers under a blue sky.
Hummingbirds are tiny acrobats. They can fly backwards and even zip around upside-down. Image: Two hummingbirds fly through a blue sky with a tree branch in the background. One hummingbird with magenta, green and white feathers is flying upside-down. He is looking up at another hummingbird with green and white feathers and saying, “Look what I can do!”
While hummers can do many tricks, one thing they can’t do is bend their wings as they fly. That’s what allows other birds to squeeze through tight spaces. Image: A pigeon flies through two forked branches of a tree by folding its wings close to its body. It makes a “fwoosh!” noise as it soars through. A hummingbird sits on a nearby branch in the forest, watching the pigeon. The hummingbird’s thought bubble says, “How is she doing that??” Text (below image): So it’s been a mystery just how hummingbirds fit through gaps between branches that are smaller than their wingspans.
To find out, researchers at the University of California, Berkeley, trained four hummers to fly between two feeders inside an arena. Image: A diagram shows the layout of a two-roomed arena. In the front room, a hummingbird drinks from a fake yellow flower on the wall. The hummingbird is saying, “Yum, yum, yum.” Two cameras watch the hummingbird from the floor and another wall of this room. A third wall of the room has a small hole in it. The hummingbird can fly through this hole to reach the second room of the arena, which has its own fake flower that the hummingbird can drink from. Text (below image): The feeders were separated by a wall with a hole as wide or narrower than the hummingbirds’ wingspan.
High-speed cameras revealed that, at first, the birds flapped their wings to fly through the gap sideways. Image (top): A side view of a hummingbird shows how it flies sideways through a gap, bringing its left wing forward and its right wing backward. As the hummingbird flies sideways through the gap, it says, “I’m just gonna scooch through here…” Image (bottom): A bottom view of the same hummingbird shows how it brings its left wing forward and right wing backward to scooch through the gap.
This method might allow hummingbirds to quickly backtrack if they run into obstacles and want to reroute. Image: A hummingbird has just flow sideways through two forked branches but finds a dense bush with pink flowers on the other side that it cannot get through. The hummingbird is saying, “Oops, never mind!” A yellow arrow shows that it’s starting to fly back in the direction it came.
After traveling through the gap a few times, though, the birds learned to flatten their wings against their bodies. And they shot through the hole like bullets. Image (top): A side view of the hummingbird shows how it pins its wings to its body to zip through a gap, saying “Bombs away!” as it goes. Image (bottom): A bottom view of the same hummingbird shows how its wings lay flat against its body as it pulls this maneuver.
JoAnna Wendel

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Erin I. Garcia de Jesús is a staff writer at Science News. She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.

Maria Temming is the Assistant Managing Editor at Science News Explores. She has bachelor's degrees in physics and English, and a master's in science writing.

JoAnna Wendel is a freelance science writer and cartoonist in Portland, Ore. She loves to make comics about all types of science, but she especially loves drawing planets, invertebrates and sea creatures. When she's not drawing, JoAnna is probably reading, hiking or hanging out with her cat, Pancake.

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