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January 28, 2012

U of A scientists know why the caged bird sings


EDMONTON - When University of Alberta psychology professor Chris Sturdy began studying songbirds to better understand animal evolution and human problems associated with speech and language, he wasn’t sure whether a creature with a chickpea-sized brain could be trained to participate in his experiments.
Since then, there have been no end of surprises coming from his laboratory, which is funded by National Science and Engineering Research Council.
In comparing the ability of humans, mammals and birds to be trained to discriminate between subtly different series of musical notes, for example, some songbirds fared much better than rats, which did poorly, and better than humans, even when the humans had previous musical training.
Sturdy and his colleagues learned that female chickadees responded differently when exposed to the sound of a dominant male versus a subordinate male.
They also responded relatively calmly when presented with a mounted Great Horned Owl along with a recording of the sound that a live one makes in the wild. However, those same chickadees got much more excited when subjected to the sight and call of the much smaller Saw-whet owl, a predator that has a shorter wing span and is better equipped to hunt them down in the trees and bushes.
“Generally speaking, birds learn their vocalizations in a manner analogous to human speech learning, so understanding songbirds as a non-human model that can be reared and tested in controlled environments may allow us to understand something about the human condition,” says Sturdy, who has 20 conditioning chambers in his lab at the university and five computers that constantly play and record songs of the birds.
“It’s humbling to test these birds and see how similar they are to us in the way they respond to stimuli. They really are a lot smarter than most people think.”
The idea that the brain of a songbird can tell us something about human nature and the way our brains work is not as outlandish as it might sound. Like children, songbirds learn how to sing from their parents.
And research has shown that like birds, humans value music because of the emotions it brings out.
While a crying baby, for example, may be calmed by Brahms’s lullaby, the music of Michael Jackson or LMFAO has the ability to stimulate the brain’s reward centre sufficiently to get a man with no discernible dancing abilities to get up at a party and make a fool of himself.
Research has also shown that the sound of music has the ability to improve memory. Played at 60 beats per minute, Mozart’s music, for example, has been shown to activate both the left and right brain. Triggered simultaneously in this way, the human brain is better able to learn and retain information. That may be why some actors tend to sing the words of a play when they are trying to memorize their lines.
Songbirds, like humans, are one of only six animal groups — including bats, parrots, hummingbirds, and cetaceous creatures such as whales and dolphins — that are able to learn by communicating vocally.
They also possess a highly evolved network of interconnected brain regions that control their ability to sing, hear and perceive the meaning of a multitude of sounds they hear in the wild every day.
Like dogs, not all songbirds are equal in their ability to learn. Black-capped chickadees, such as those found in Alberta’s river valleys, seem to have an especially sophisticated system of communicating.
No one knows exactly why, but it may have something to do with their social structure. Chickadees flock up in fall and winter before paring up in spring. They are one of the few songbirds you hear communicating in the dead of winter.
The notion that songbirds can learn actually goes back to the days of Mozart, when cross-fostering experiments resulted in a Linnet (a small finch-like bird) learning to sing like a skylark.
But the idea that they could tell us something about humans didn’t really get started until the 1980s, when a small group of scientists, including Canadian scientist Ron Weisman, Sturdy’s mentor, began investigating the possibilities in systematic and sophisticated ways.
Now it’s a fast growing field, with major universities from around the world playing host to songbird labs such as Sturdy’s.
As sophisticated as these ways are, the basic protocol for training a songbird in a lab is as simple as it gets in science.
Songbirds are rewarded with food for doing things right and punished for getting them wrong, much as dog-owners do when they’re training puppies. In the case of songbirds, Sturdy and his students simply turn off the lights when the birds get the wrong answer.
To make sure that humans participating in some studies are trying their best, they are given a financial reward.
There are many reasons why songbirds communicate.
“Ron Weisman, my old boss, used to joke that it was all about sex and violence,” says Sturdy. “Funny as it sounds, there’s a great deal of truth to it. Birds sing to woo a mate, stake out a territory and defend it against other birds and predators.”
As complex as some of these bird calls can be, they involve just four note types, which scientists in this field of study label as A, B, C, and D.
Like scat and jazz singers who use predetermined formulas in innovative ways, chickadees will repeat the A or the B or the C or D notes and drop one of them in the sequencing. But unlike the improvised melodic line of a scat singer, they never mix up the sequence. D never follows A, for example and D will never follow C.
Sturdy acknowledges that he’s been compared to Dr. Doolittle more than once in his career.
“I have been known to go out in my backyard to try and communicate with the birds to get the right response, just as most Canadians do when they go on a camping trip to see if they can get a response from a common loon. I’m not always successful, but it is gratifying when you get the response you are looking for.”
Sturdy is convinced that the songbird’s ability to learn is much greater than the abilities he has been able measure so far in his lab.
“Part of the problem is that we are dealing with birds in a lab that are not mating or looking out for predators. But I think the biggest thing is that we are probably not always asking the right questions when we design these experiments. It’s not the songbird that the problem, it’s us.”

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