Studies of our feathered friends reveal neurological twists that one day might help human brains.
University of Washington researchers say spring's chorus of bird song may hold insights on human learning and such disorders as strokes and Alzheimer's. Biologist Mike Beecher fastens a stuffed sparrow to a tree limb in Discovery Park in Seattle.
Why wasn't this intruder getting the message?
The lord of the manor had warned him repeatedly to back off, with threatening gestures and loud admonitions. But the trespasser just sat there -- singing.
The time for detente was past. In a flurry of feathers, the resident sparrow dived for his challenger's head.
"They have personalities," said Michael Beecher, watching from a few feet away as the furious bird pecked and clawed at the rival male. "Some are more laid back, but this is an attacking bird."
The University of Washington biologist stepped in to terminate the brawl, retrieving the stuffed sparrow and mini-speaker that tricked the real bird into believing his territory had been overrun.
Foe vanquished, the sparrow fluffed himself up, perched high in a tree and let loose a cascade of trills and whistles.
"That's the king-of-the-mountain song," Beecher said.
Beecher understands better than most the messages that pass between song sparrows. He and his students have been studying the birds' communication patterns in Seattle's Discovery Park for more than 25 years. The duel he orchestrated on a recent morning provided an opportunity to record the sotto voce song that males use only when confronting interlopers -- a kind of in-your-face undertone that hisses: I mean business.
The way birds learn their songs is similar to the way babies learn to talk and adults master a golf swing, University of Washington brain researchers say. And studies of the seasonal changes in bird brains are revealing neurological twists that one day might be harnessed to heal human brains damaged by stroke, Alzheimer's disease and other disorders.
"The strength of the songbird system is that you can go down to the very detailed, micro-level ... then explain how that leads to changes in behavior," UW neurobiologist David Perkel said. "That's something not a lot of neuroscience can do."
It was research on songbirds that upset the long-held notion that most animals -- and most certainly humans -- were born with all the gray matter they would ever have. Working with canaries and chickadees in the 1980s, Fernando Nottebohm at Rockefeller University found brain regions associated with song and the ability to locate hidden caches of food were constantly birthing new cells.
Scientists soon discovered neurons sprouting in other brain areas and in the brains of other animals -- including Homo sapiens.
Many birds, such as gulls and flycatchers, are hatched with vocalizations hard-wired into their brains. But the 4,000 species that make up songbirds must learn how to sing properly. Perkel's research focuses on zebra finches, which study and memorize the songs of adults. At first, the fledglings jabber or sing snippets, gradually improving until what comes out of their beaks matches the template in their memory banks.
"It's a model for speech learning in humans," Perkel said.
Charles Darwin was among the first to suggest a connection, noting similarities between the babbling of baby birds and the nonsense syllables of human infants. Perkel is convinced the parallels extend to all types of learning that require practice and feedback, from memorizing multiplication tables to honing a golf swing or ski jump.
"We think that by cracking this circuit in birds," he said, "it will have a large impact on our understanding of the brain mechanisms involved in learning a broad variety of skills."