Human language is governed by a set of rules known as syntax, which ultimately controls how we arrange words and phrases to convey meaning when communicating with someone. Until now, this social behavior was thought to be unique to humans.
The Japanese great tit - a bird closely related to the North American chickadee - is known for its diverse vocal repertoire. An international team of researchers recently discovered these birds follow a specific set of rules to combine their calls and communicate complex messages, much like humans do.
The Japanese great tit has a few different note types, which researchers named A, B, C and D. In response to a predator sighting, for example, the birds may use a string of notes in what is known as the "ABC" call, signaling to others they should "scan for danger."
"We now have good evidence that animal communication systems share many of the basic properties of human language," said Toshitaka Suzuki, lead author and postdoctoral fellow in the Department of Evolutionary Studies at Japan's Graduate University for Advanced Studies. "For example, mammals and birds can use specific call types to denote specific objects, and Japanese great tits can combine different 'words' to send a compound message."
For instance, the "ABC" call is often followed by the "D" call, which instructs other birds to approach. When the ABC-D call is made, the birds fly toward the speaker but still scan the area for predators first.
Suzuki and his team played recorded calls to a total of 21 wild adult Japanese great tits. They found that the listening birds did exactly as the calls commanded. However, when the call was ordered incorrectly, such as D-ABC, the birds do not respond.
"This study demonstrates that syntax is not unique to human language, but also evolved independently in birds," co-author David Wheatcroft, a post doc researcher at the Department of Ecology and Genetics at Uppsala University, added. "Understanding why syntax has evolved in tits can give insights into its evolution in humans."
The next step, researchers say, is to identify other birds that use rules like these when communicating. Their findings were recently published in the journal Nature Communications.
