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Researchers Discover Hummingbirds May Use Counting To Find Their Flowers


Hummingbirds - they are delightful - so tiny, yet so fast, so resilient and also, according to a new study, math whizzes.


GARCIA-NAVARRO: With wings that beat 10 to 15 times a second, hummingbirds can feed from hundreds of flowers in a day. But when biologists at the University of St. Andrews in Scotland noticed the birds returning to the same spots...

MARIA TELLO-RAMOS: We then wanted to know, are they using different types of information to remember all these locations?

GARCIA-NAVARRO: That's researcher Maria Tello-Ramos, part of a team at St. Andrews that wondered whether the hummingbirds might, in fact, be counting. That's right - counting - one, two, three and so on. So the team created an experiment lining up 10 artificial flowers and filling one of them with sugar, a tasty reward.

TELLO-RAMOS: So we first gave them the first flower rewarded until it learned, and then we repeated that for the second, the third and the fourth flower.

GARCIA-NAVARRO: To make sure the birds were counting rather than remembering where in the room a particular flower was located, Tello-Ramos and her teammates changed the flowers' location and spaced them out differently in different trials. Lo and behold...

TELLO-RAMOS: We saw that for the majorities of the visits, the birds went to the correct ordinal flower despite of where in their territory the array was and also the distance between the flowers.

GARCIA-NAVARRO: Hummingbirds aren't the only animals with this ability. Guppies, rats and monkeys can count, too. So far, the birds' counting skills are limited.

TELLO-RAMOS: To this day, they can order a sequence up to four.

GARCIA-NAVARRO: But knowing how to count might be uniquely important to hummingbirds' survival. It takes a lot to power those whirring wings, which means it's important not to waste energy going places that are depleted of food.

TELLO-RAMOS: If they remember, this is the first flower I go, this is the second, this is the third, and then if, in the middle of the day, the third patch now is depleted, they know that from the third, they just need to move then to the fourth. And in subsequent bouts, they can just skip the third and go directly to the fourth.

GARCIA-NAVARRO: And that's a big deal for these little creatures, which are - even better - fun to work with, too.

TELLO-RAMOS: These species in particular are very feisty. They're very territorial. In the morning, where you're setting up the arrays, they sometimes come near you and they're like, OK, hurry up. I'm hungry. Put the flowers, please.


GARCIA-NAVARRO: That's Maria Tello-Ramos of the University of St. Andrews in Scotland. Transcript provided by NPR, Copyright NPR.