How birds learn songs likened to way humans learn speech

Learning how baby sparrows learn to sing their songs could provide clues to how humans learn to speak languages.

University of Utah biologist Gary J. Rose and his colleagues have taught baby sparrows to sing a complete song, even though the birds were exposed only to overlapping segments of the tune rather than the full melody.

Their study, published in Wednesday's issue of the journal Nature, provides clues about how musical memories are stored in the brain and how those memories help birds learn to sing. Rose is the principal author of the study.

"There are strong parallels between song learning in birds and speech learning in humans," Rose said. "Like humans, songbirds learn particular regional dialects, so they represent excellent opportunities to study the physiological basis of language. If we can understand something about how song is represented in their brains, then maybe we can better understand how speech learning occurs in humans and, when it goes awry, how we might go about fixing it."

Co-author Stephanie Plamondon, a doctoral student in neuroscience, said the scientists gave the birds just pieces of the song and they were able to assemble a complete song.

"A full song or a complete sentence isn't required to learn the song, only an association between phrases of the song."

Songbirds must hear their species' songs when they are young or they fail to learn to sing them, Rose said. Such birds produce very simple songs, mostly repeated whistles.

Birds learn to sing in stages. First, there is a subsong phase in which they babble softly, almost like human infants. Then they undergo a phase when they practice singing for eight or nine months and the bird is producing a song and comparing it to the memory he has formed, Plamondon said.

After that, birds undergo "crystallization," which means their song is crystallized or essentially set in stone, at least until the next mating season, when some changes can occur.

The Utah biologists tested a theory dealing with the long-term "auditory memory" formed by young sparrows when they first hear other sparrows sing. Scientists want to know how that memory is stored in the brain and how that memory is used as the birds learn to sing weeks later.

The complete white-crowned sparrow song has five segments or snippets — researchers call them phrases — represented by the letters ABCDE. "A" is a characteristic opening whistle; "B" is a note complex or several musical notes in a specific sequence; "C" is a buzzing sound; "D" is a trilling sound; and "E" is another note complex.