London: A new study has shown that birds too have their own set of grammatical rules, a feature previously thought to be specific to humans only.
According to Kentaro Abe of Kyoto University, Japan, Bengal finches have their own versions of rules – known as syntax.
"Songbirds have a spontaneous ability to process syntactic structures in their songs," New Scientist quoted Abe as saying.
His team played jumbled "ungrammatical" remixes of finch songs to the birds and measured the response calls, to show a sense of syntax in the animals.
Abe said that only his finches have been shown to have a form of grammar in their utterances. Similar claims have been made for whale song, however.
In the wild, Bengal finches call back vigorously whenever they hear unfamiliar songs, usually from intruding finches. In the lab, Abe and colleague Dai Watanabe of the Japan Science and Technology Agency in Saitama exploited these reactions to gauge whether finches could notice "ungrammatical" songs.
"What we found was unexpected," he said.
The birds reacted to only one of the four jumbled versions, called SEQ2, as if they noticed it violated some rule of grammar, whereas the other three remixes didn``t. Almost 90 per cent of the birds tested responded in this way.
"This indicates the existence of a specific rule in the sequential orderings of syllables in their songs, shared within the social community," he added.