Good Grammar Is a Matter of Life or Death for Japanese Tits
These chatty birds string their sentences together in a specific order to rally friends and fend off foes.
In a dimly lit forest, a sneakymarten silentlystalks a group of Japanese Tits fluttering in the treetops. Then, suddenly,one of the little birds spots the invader andbelts out a series of buzzy chirps. In response, the titsassemble and prepare for a preemptive attack on the predator.
It's a scene that regularly plays out in the woodlands of Japan and eastern Russia, where the birds call home, and therapidmobilization is the result of theirimpeccable communication skills. When danger like the marten is spotted, aflock member voicesa "mobbing call"—a combination of chirps called an “alert-recruitment” sequence—to rally the troops, explains Toshitaka Suzuki, a postdoctoral expert on animal communicationat Kyoto University’s Center for Ecological Research. While observing these sociable birds in the wild, Suzuki noticed that they also understand the meaning of calls from their close cousin, the Willow Tit. So, he ventured that Japanese Tits may rely on a rudimentary form of grammar to relaymessagesand provoke actions.
In a new study published this month in the journal,Suzuki and his research team tested this ideaandfound that Japanese Tits do in fact talk to each other using clear syntax rules. Even more surprising, the researchers discovered that the chickadee-like passerines can find meaning in chirpy sentences that they’ve never heard before—as long as they follow the familiar “word order.”
To test the birds’ comprehension, Suzuki and his team produced a small playlist of tit sounds. The researchers labeled the usual alarm call, which alerts the birds to predators such as martens, shrikes, and crows and prompts them to survey the area, as “ABC.” The recruitment call, which gathers the birds for anything from mealtime to mobbing, was simply deemed “D.” Using speakers placed in trees, the group projectedthese different calls and gauged the tits' reactions.Upon hearingthe, the birds acted as expected: They checked for looming danger and thenapproached the speaker. In the next experiment, however, the scientists reversed the call by playing the recruitment phrase first. The birds didn’t respond.
Next, the researchers spliced the Japanese Tit’s alarm call with the Willow Tit’sӓӓrecruitment call.Though the two species do mingle together in the wild, they’ve never been heard to sample each other’s sounds. Yet the invoked a strong reaction in the Japanese Tits: They treated it as if it were a typical “A-D” sentence. The team then tried it in , and again, the birds ignored it.
These reactions andnon-reactionssuggest that tits need syntax to make sense of commands. Rather than telling the flock to mob right away, it’s important to educate the birds on the threat first. Similar grammatical logic has been exhibited in other species like the Carolina Chickadee, says, a PhD candidate in behavioral ecologyat the University of Nevada, who was not involved in the study. Though Suzuki’s work does an excellent job furthering our understanding of bird communication, Branch says, it would also be interesting to see if Willow Tits respond to the same remixes.
And that's exactly what Suzuki plans to do. For his next experiments, he wantsto see whether other closely related tit species are able to converse using the samesyntaxrules. “Future comparative work mayuncover the socioecological factors driving the evolution of grammatical communication in this avian group,” he says. Ultimately, that could help researchersfurther understandhow language emerged and matured across the bird world.