The sounds of birdsong and baby babble may not have an obvious association, but researchers have discovered important similarities in the way birds and humans learn vocalisation.
"Babies follow a very similar pattern to chicks when learning how to speak," Dr Karen Spencer, from the University of Glasgow, told the Festival of Science yesterday. "They share an initial sensitive period for the memorisation phase, followed by a series of vocal stages. The baby equivalent of this would be the explosion of babbling from gurgles."
The process of "vocal learning" involves learning vocalisation through imitation. Humans and birds are part of a small group which exhibit this vocal learning and Dr Spencer is interested in the stages of the process.
"When a young bird emerges from its egg, it is unable to start singing immediately. It begins by listening to the sounds produced by its parents and other species members and memorises them," Dr Spencer said.
"In the next stage of the learning process the bird uses the memorised sounds as a framework for producing sounds that are similar, via imitation. Finally, young birds practise their song, which goes through several stages until they refine it to the tune they require in adulthood."
She explained that there were parallels between this process and the developmental pathway human babies use when learning to speak. These similarities have interested scientists for years, but new tools are enabling them to study the brain activity and investigate the genes involved.
"One gene known to be involved in human speech has also been found in songbirds, which exhibit patterns of expression identical to those seen in humans. These exciting results give us a new route by which to investigate the origins of vocal learning," Dr Spencer said. "Recent advances in brain imaging, such as functional magnetic resonance imaging, also now allow scientists to look at the activity of the entire brain in birds while they are awake and listening to song. These methodologies will undoubtedly be used to enhance our knowledge of how sounds are processed."
While there was no evidence that birdsong formed a "language", she contended that the usefulness of a bird's song in communicating with other birds should not be discounted.
"The most interesting uses for song are those of mate attraction, and while females may not have a 'conversation' with a courting male, they are able to use specific rules to determine how sexy a male may be by listening to his song," she said.