Bird Song Stuck in the Head

SEATTLE--Some birds that learn to sing just as people must learn to talk appear to have more cues to learning wired into their brains than researchers had previously recognized. "We've known that they had some innate cues," Peter Marler, an animal behaviorist at the University of California, Davis, told an audience here Saturday at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW). "But it now appears that the extent of that innate knowledge is much more pervasive than we ever expected."

Most birds are born with their species' tunes embedded in their brains--that is, they can begin to sing their songs without hearing them first. Those that learn to sing by mimicking other members of the species are rare birds indeed. Of 27 orders of birds, only three--parrots, hummingbirds, and songbirds--have this talent. But even these learners have some neuronal cues that tell them what they should be singing, Marler says. For instance, recent studies in his lab have found that newly fledged white-crowned sparrows, a passerine, respond to a wide range of short bursts of their species's song. "They recognize even a small fragment--just a few notes of the song--even when they're only 2 weeks old," Marler says.

These young birds also appear to be equipped with innate knowledge about their species's song's syntax--how all the fragments fit together. For instance, birds raised in isolation produce a song resembling the species song--but a warble unlikely to win them a mate. "It's as if they have to hear their song first," Marler says. "This triggers some sort of prerecording that gets the process going."

Marler speculates that a similar mechanism may underlie language learning in human babies. "It may be why the learning of language can proceed so incredibly quickly," he says. Other experts think this idea has merit. The research "does seem to suggest some striking similarities between bird and human [brains]," says Patricia Kuhl, an expert on human language acquisition at the University of Washington. "The whole idea that innate knowledge plays a much more prominent role in behavior than we thought is very exciting," adds Marler.