Calgary

Hummingbirds can count to find favourite flowers, even with brains 7,000 times smaller than humans

How can hummingbirds find their preferred flowers? By counting, say researchers. Andrew Hurly, a professor emeritus in biology at the University of Lethbridge, is one of the co-authors of a new study into hummingbird cognition.

Study might provide better understand how hummingbirds forage in the wild

A hummingbird selecting the first flower in the array set up by researchers. (Submitted by Andrew Hurly)

How can hummingbirds find their preferred flowers? By counting, say researchers.

Andrew Hurly, a professor emeritus in biology at the University of Lethbridge, is one of the co-authors of a new study into hummingbird cognition and spoke with CBC's Calgary Eyeopener.

He said hummingbirds are "amazingly good at remembering places."

For example, if a person placed a bird feeder outside that a hummingbird returned to several times and then one day moved it one metre away from where it initially was, the bird will notice, Hurly said.

"The hummingbird will fly in and hover where the feeder was, look around, see the feeder and go feed from it … they're remembering where that feeder is, presumably with respect to some landmarks," Hurly said.

"Their little brains are doing amazing things — things that I can't do."

But now, researchers have found that with rufous hummingbirds, common to Alberta, the male can also determine the position of its preferred flower based on its position in a sequence of flowers. The technique is known as ordinality and is similar to the ability of a human being able to determine that the letter "C" in the English alphabet comes third.

In the study, published in a Royal Society Publishing journal, researchers put out a series of artificial flowers, some with food in them, to find out if the hummingbirds could tell the difference between each of the flowers and where the flowers were in relation to each other.

Andy Hurly, pictured several years ago, filling an artificial flower with sugar solution for an experiment. (Bernie Wirzba )

The nine birds that were part of the experiment figured it out within just a few hours, Hurly said.

And when the researchers moved the flowers random distances apart, they found the birds were not returning to the flowers based on remembering the distance to get to each flower — but based on where each flower was in the sequence.

"That way we can ask, "do they remember the fourth flower as being 60 centimetres from the start or do they remember it as the fourth?" Hurly said.

"The answer was yes, it is the fourth flower. It's not the distance from the end of the array it is in fact the fourth flower.

Hurly said the brains of hummingbirds are about 7,000 times smaller than a typical human brain — they're about the size of a large grain of rice or small bean.

"Nonetheless, it's very sophisticated and it does hummingbird things really well," he said. 

The research might help scientists better understand how hummingbirds forage in the wild.

Hurly explained that each flower has a tiny bit of nectar in it and it takes several hours for that to refill.

"So if a hummingbird had 50 flowers in a trapline [its sequence of flowers it visits], by the time it finished the last flower, it could start again and run the same route and the flowers might have had time to recharge some of their nectar," Hurly said.


With files from the Calgary Eyeopener.

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