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Finches tweet using grammar

Two Bengalese finch

Bengalese finches are easily domesticated, very social and do a lot of vocalising (Source: Kentaro Abe /University of Kyoto)

Perfect tweets We may not be able to use "bird brain" as an insult any more. Japanese scientists have discovered that songbirds are using their own form of grammar.

The study challenges the belief that only humans are able to use grammatical rules to process strings of sound such as sentences.

The experiments, described in Nature Neuroscience this week, were carried out on Bengalese finches by Dr Kentaro Abe and Professor Dai Watanabe of the University of Kyoto in Japan.

Bengalese finches are tiny birds, which are easily domesticated and very social. They also do a lot of vocalising. Each male has his own song call, which he varies quite a bit, but is distinctively his own, explains Abe. When he hears another male, his response is usually to make a burst of calls in reply (about 30 calls in 10 seconds).

Birdsong can be thought of as being like a sentence, with the different sounds being like words. The scientists played jumbled-up birdsongs to individual finches to see whether the birds responded with the usual burst of calls to the jumbled songs.

To their surprise they found that there were some jumbled songs that elicited a call-burst response and some that did not. Even more surprising: all the birds responded in the same way. If one bird ignored a jumbled call, all the other birds ignored that call too.

It seems that the order of syllables matters to the birds, and that suggests grammar in action.

"It's as if you were presented with a sentence like 'we will go to the zoo tomorrow'", says Professor Gisela Kaplan, an authority on birdsong at the University of New England.

"Some versions of the sentence such as 'tomorrow we will go to the zoo' and 'we will go to the zoo tomorrow' are grammatically acceptable, others like 'zoo go we will tomorrow the to' are not."

"Obviously with these birds the syllables can't just be put anywhere, and that suggests that humans aren't unique in being able to order sound logically. The fact that birds can do this, even if only at a simple level, is mind boggling", says Kaplan.

Better than monkeys?

In further experiments the scientists showed that the birds were able to learn new artificial grammar rules very quickly.

"Songbirds [can] discriminate auditory information that is much more complex than monkeys can handle", say the researchers.

They also managed to identify the part of the bird's brain that is important in doing the grammar processing.

Kaplan says this is particularly exciting because it means that birds can be used as animal models to better understand how the human brain processes language.

"Our results indicate that syllable sequences in birdsongs convey some information", say the Japanese researchers, which leads one to wonder whether birds extract any meaning from their songs.

"It may well mean something to the bird," says Kaplan, "otherwise why would they bother?"

Tags: animals, animal-behaviour, birds