In the previous research, this research group approached the sound source while being cautious when Shijukara listened to the warning sound (Petsupi) and the collective voice (Dijijiji) in a fixed word order (Petupi Jijijiji), but the synthetic sound (the word order was reversed). Discovered that it does not react to (jijijiji peetsupi).In other words, the existence of a grammatical rule that issues "warning" first and continues "set" to it has been shown, but is this rule applicable to understanding new sentences like human grammatical ability? Was unknown.

　Therefore, in this study, we synthesized new sentences from the collective voice of the willow tit (Dee Dee) and the warning sound of the great tit (Petsupi), where the great tit live together in a group, and experimented to see if the great tit could correctly read the meaning.As a result, when I heard the tone row (Petupi Dee Dee) according to the grammar of "Caution → Set", I approached the sound source while being cautious of the surroundings, but for the tone row (Dee Dee Dee Dee) that violated the grammar. Did not react.In other words, it became clear that if the great tit applies the grammatical rules, the meaning can be correctly understood even with the tone row that is heard for the first time.

　This achievement is not only the first to reveal the flexibility of grammatical ability in animals, but it is also an important discovery in clarifying how human language has evolved.

Paper information:[Current Biology] Wild birds use an ordering rule to decode novel call sequences