We know that a mouse can fit through a hole as narrow as a pencil, but hummingbirds also know how to squeeze through the narrowest holes in their search for food. Now it is finally clear how they do that.
Hummingbirds are known for two characteristics: with a length of 7 to 13 centimeters, they are tiny. A large insect is larger. And they can also fly very well. They flap their wings quickly and are thus able to hang in one place, turn around very quickly and even fly backwards. However, they are less able to fold their wings than many other birds. “Unless hummingbirds use some other strategy to maneuver through narrow openings, they cannot fly through gaps less than a wingspan wide,” said researcher Marc Badger of the University of California, Berkeley.
Looking for sugar
But since they can, the question for a long time was: how? And there Badger is with colleagues, including researcher Kathryn McClain, found out. The swift birds have two unique ways to get through gaps that are barely half their wingspan.
“We set up a two-part flying arena and wondered how we could train the birds to fly through a 16 square centimeter gap in the divider that divides the arena into two halves. That’s when Kathryn came up with the great idea of using alternate rewards,” says Badger, who explains that a little sugar solution was only added to the critters’ feeder if they managed to return to the feeder across the street to keep the hummingbirds alive. which have a wingspan of about 12 centimeters, to flutter back and forth.
Smaller and smaller holes
Once they succeeded, the researchers started making it a little more difficult. The diameter through which the birds had to get through increased from 16 to 12 to finally 6 centimeters, so half a wingspan. In the meantime, they filmed the birds’ maneuvers. But that’s when things started: To figure out exactly how the hummingbirds did it, Badger wrote a computer program that tracked the position of the beak as they approached and passed through the opening. The location of the tips of the wings was also mapped to calculate their wing positions as they flew through the hole.
A beautiful hummingbird. Photo: OGPhoto
That made a lot clear. The hummingbirds used two unique strategies. They hovered briefly in front of the opening to study it before passing through sideways. They moved one wing forward while keeping the second one behind them. They almost formed a cross, still flapping their wings to get through the opening. In the second strategy, they both moved their wings back, close to their bodies, and shot forward like a bullet, beak first. Then they immediately moved their wings forward and began to flap again when they were safely through the hole.
More and more self-confidence
How smart the hummingbirds are is evident from their approach: in the beginning, when they do not yet know exactly how big the hole is, they choose the first, more careful method. But once they have done this a few times, they become more confident and shoot through the hole with their beak forward using the second method. Only at the smallest openings, less than a wingspan wide, did the birds have no choice but to pass through with their wings backwards to avoid collisions.
With the help of these two strategies, these little hummingbirds manage to fly through small holes in their search for food, despite their poor ability to fold their wings. At first they move slowly and carefully flying sideways through the hole, but as they become bolder they simply go beak first. And that almost always goes well. Only once in the experiment did a bird collide with the barrier, but even then it recovered quickly and made a successful second attempt to get to its tasty sugar snack on the other side of the room.
2023-11-11 14:46:05
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