Songbird's syntax demonstration rewrites book on communication
Language rules for combining words to generate novel meanings - known as syntax - can no longer be thought of as uniquely human.
Scientists have found that a Japanese songbird follows similar rules to communicate a variety of messages.
The Japanese great tit was already famed for its wide vocal repertoire. Threatened by numerous predators, the small bird produces a variety of different calls.
Researchers observed the behaviour of the birds while playing back recordings of their own singing.
Calls were broken down into "note types", designated A, B,C and D, which were combined in different ways.
The team showed that ABC calls signified "scan the horizon for danger", for example when encountering a perched predator.
"D" calls, translated as "come here", were used when discovering a new food source or enticing a partner to a nest box.
Playing a combination ABC-D call caused the birds both to approach the loudspeaker and scan for predators.
But when the call ordering was artificially reversed (D-ABC) it produced no response.
"This study demonstrates that syntax is not unique to human language, but also evolved independently in birds," said Dr David Wheatcroft, one of the researchers from Uppsala University in Sweden.
"Understanding why syntax has evolved in tits can give insights into its evolution in humans."
The findings are reported in the journal Nature Communications.