14 DAY TRIAL // "We made a chicken sound like a quail, proving that the way the birds vocalize is not affected by learning. They are born with a song in their head."
Over the past 12 years, Evan Balaban, a behavioral neuroscientist at McGill University in Montreal, and colleagues in the United States swapped brain cells from quail and chicken embryos to see the effects on the particular characteristics of each bird.
When they hatched, the chickens looked normal, except for a few dark quail feathers sprouting from their heads, but sang two introductory notes followed by the long trill of a quail song instead of a cock-a-doodle-doo. Computers were used to analyze the acoustics but the different sounds were recognizable just by listening.
In the past, researchers believed birds learned their songs from their parents or their brothers. But studies have shown they are born already hardwired with a tune in mind.
The same process is likely at work with human infants who are immediately attracted to speech, Balaban said. Bird and human brains are roughly connected the same way. "So far, there is no evidence that a child born in Nepal has a greater propensity for learning Nepalese than French or English. But, this may explain why they learn to talk instead of learning how to bark like a dog," he said.
In other experiments, chickens were made to respond to quail danger warnings by running toward a parent to seek protection, while others bobbed their heads the way quails do when they sing.
Through a process of elimination, Balaban and his team found a group of cells that make quail sing like a quail. In a chicken, the quail cells seemed to send out a chemical signal to tell its embryonic brain to build a particular cell network responsible for the quail song.
"We don't have a good understanding of how complicated circuits in the brain develop. Even simple behaviors require many parts of the brain talking to each other," Balaban said.
The findings could help scientists better understand human language acquisition and development, as well as lead to new treatments for brain disorders such as Parkinson's disease. "I'm hoping to understand how nerve cells talk to each other and organize circuits to form patterns of behavior so that someday we can fix damaged circuits."