Syntax for Island Birds Is for the Birds

Apparently regional accents and grammar's on-going breakdown in tweets isn’t such a uniquely human phenomenon. The songs of chaffinches, a fairly common European songbird, lose their syntax among some populations.

According to biologist Robert F. Lachlan, a "chaffinch from mainland Europe always sounds like a chaffinch from mainland Europe.” The small, rust colored birds’ songs generally don’t vary much, except in two specific places: at the very end of two archipelagoes. As the birds move out to the ends of the chains of the Azore and the Canary Islands, the less-strict birds follow syntax. They’re just free-chirping and tweeting like “an island of Charlie Parkers.”

The birds gradually moved out across the islands over the course of the last half a million years. As they went, island-by-island, their songs changed. The chaffinches sang similar notes, but not in as-strict combinations. The syntax, or rules for arranging the songs, were breaking down. By the end of the island chains, "the syntax isn't just changing, it's disappearing," said Lachlan. "It's not about changing the rules, it's about losing them."

Lachlan isn’t quite sure why this is the case. Since chaffinches sing to attract mates, and there’s less competing noise from other songbirds at the ends of the island chains, maybe chaffinches no longer need to follow strict syntax for females to pick out their song and find them. But there must be something else going on, because, in spite of having twice as many competing species of songbirds, the chaffinches on the Canary Islands had even less structure than their counterparts on the Azores.

Bird songs are a mix of learned behavior and genetics, and are, in the estimation of some, the closest parallel to human speech in the animal kingdom. Both birds and people learn complex vocalizations from their elders. Both birds and humans have evolved complex portions of the forebrain devoted to getting down fine motor skills to allow speech. Lachlan’s research seems to indicate that the difference is more tied to nurture than nature.

Maybe with the smaller population of their fellow chaffinches, there wasn’t anyone around to teach the next generation, Lachlan said. Or maybe, within the smaller bird population, a varied repertoire becomes more important. The results of his research will be published Oct. 7 in journal Current Biology.

Other studies have explored bird syntax using Bengal finches, cousins of the canary and chaffinch, and found that several seperate populations of Bengal finches would all react to a specific cut-up and replayed recording of Bengal-finch song, but not others, revealing that syntax matters, at least to them. Other very social animals like whales, bats and primates exhibit some syntax, and dogs can make sense of our sentences.

Chaffinches who have moved to the ends of islands in the balmy Atlantic, unlike Bengal finches, don't seem to care and they cheerfully batter their language, which opens the possibility of some sort of chaffinch My Fair Lady.