By DAWN WALTON
Toronto Globe and Mail
March 07, 2006
Researchers have discovered that the tiny rufous hummingbird, which each day feeds on hundreds of flowers containing just a fraction of a drop of nectar, has a mighty memory that can pinpoint the location of the flowers it has visited and when the nectar in each would be replenished.
"Not bad for a bird with a brain 7,000 times smaller than our own," said Andrew Hurly, a biology professor at the University of Lethbridge, who co-wrote the groundbreaking study published in Tuesday's issue of the journal Current Biology.
Until now, such a knack for timing had not been observed in wild animals, and memory of specific events - where and when - was episodic thought believed to be unique to humans.
The rust-colored hummingbird, which weighs less than a nickel, is considered the most feisty and nomadic of hummingbirds.
According to the National Audubon Society, the rufous hummingbird has the longest known bird migration proportional to its body size. It travels between its wintering grounds in the southern United States and Mexico to its breeding grounds in Western Canada and as far north as Alaska.
In a bid to find out just how smart the teeny creatures are, a team of Canadian, British and Scottish researchers monitored three male hummingbirds during their summer migration to the Rocky Mountain region in the southwest corner of Alberta.
While hummingbirds are drawn to anything colorful to find food-bearing flowers, the birds in this study were first shown that they could feed from artificial flowers.
In the birds' feeding grounds, the researchers set up eight wooden stakes holding different colors of cardboard flowers, each fitted with a small nozzle filled with a sucrose solution.
Half of the flowers were refilled at 10-minute intervals, while the rest were refilled 20 minutes after they were drained.
The researchers found the birds returning to the flowers according to the refill schedule.
"It would be a horribly inefficient system if they flew all around the place visiting flowers they had already emptied," Hurly said. "As a matter of fact, they would be using more energy than they would be taking in. That's why we expected them to be able to do this, and we were, of course, delighted to find that they could indeed solve this type of problem."
The study noted that previously this ability has been shown only in experiments in which laboratory animals were given extensive training and didn't need to deal with real-world distractions, such as predators. Even more remarkably, according to the study, the birds were able to update their memories in specific intervals as they visited each flower throughout the day.
It would be like asking humans to remember with stopwatch precision - and without the help of Blackberries - where they went and when throughout the day.
"That is something I don't think I could do very accurately at all," Hurly said, laughing.
The research was funded by
the National Sciences and Engineering Research Council of Canada
and the United Kingdom's National Environment Research Council.
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