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March 08, 2016

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New evidence of language-like abilities in birds

March 8, 2016
Courtesy of the University of Zurich
and World Science staff

Sci­en­tists are re­port­ing new ev­i­dence that birds can com­mu­ni­cate mean­ing­fully to each oth­er by re-ar­rang­ing the same sounds in dif­fer­ent ways.

The abil­ity to com­bine a lim­it­ed num­ber of words and phrases to cre­ate mean­ing is called syn­tax—a hall­mark of human language. New find­ings sug­gest that birds known as jap­a­nese great tits have a form of this abil­ity as well, and they are not the only birds that may be re­veal­ing lan­guage-like abil­ities.

A japanese great tit (© U. of Zurich)


Un­til re­cent­ly, the ev­o­lu­tion of syn­tax was con­sid­ered un­ique to hu­mans, ac­cord­ing to the re­search­ers be­hind the stu­dy, ev­o­lu­tion­ary bi­ol­o­gists at The Grad­u­ate Un­ivers­ity for Ad­vanced Stud­ies in Ja­pan, the Upp­sa­la Un­ivers­ity in Swe­den and the Un­ivers­ity of Zu­rich.

Small birds, jap­a­nese great tits are known for a large vo­cal rep­er­toire. The sci­en­tists found that they use va­rious calls and com­bina­t­ions of calls to in­ter­act in spe­cif­ic situa­t­ions. 

A com­bina­t­ion of sounds known as “ABC calls,” for in­stance, means “watch out!”—the birds use them to warn each oth­er of near­by preda­tors such as a spar­row­hawk. Anoth­er type of call know as the “D calls” mean “come over here,” a call the birds use af­ter disco­vering a new source of food or when want­ing their part­ner to come to the nest.

But the birds of­ten com­bine these two calls in­to so-called “ABC-D calls” when, for in­stance, the birds en­coun­ter preda­tors and join forc­es to fright­en them away. When hear­ing a re­cord­ing of these calls played in the nat­u­ral or­der of ABC-D, the birds are alarmed and flock to­geth­er, the sci­en­tists said. But the call or­dering is ar­ti­fi­cially re­versed to D-ABC, the birds don’t re­spond.

“The re­sults lead to a bet­ter un­der­stand­ing of the un­der­ly­ing fac­tors in the ev­o­lu­tion of syn­tax. Be­cause the tits com­bine dif­fer­ent calls, they are able to cre­ate new mean­ing with their lim­it­ed vo­cab­u­lary. That al­lows them to trig­ger dif­fer­ent be­hav­ior­al re­ac­tions and co­or­di­nate com­plex so­cial in­ter­actions,” said Mi­chael Griesser of the Un­ivers­ity of Zu­rich. 

Griesser, one of the authors of a re­port on the find­ings pub­lished in the jour­nal Na­ture Com­mun­i­cat­ions, thinks these fac­tors may well have con­tri­but­ed to the de­vel­op­ment of lan­guage in hu­mans.

Last year, sci­en­tists al­so re­ported that a bird known as the chestnut-crowned bab­bler can re­ar­range mean­ingless sounds to cre­ate mean­ing­ful signals—al­so pre­vi­ously thought to be a un­iquely hu­man skill.


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Scientists are reporting new evidence that birds can communicate meaningfully to each other by re-arranging the same sounds in different ways. The ability to combine a limited number of words and phrases to create meaning is called syntax, and new findings suggest that birds known as japanese great tits have a form of this ability as well. Until recently, the evolution of syntax was considered unique to humans, according to the researchers behind the study, evolutionary biologists at The Graduate University for Advanced Studies in Japan, the Uppsala University in Sweden and the University of Zurich. Small birds, the japanese great tits are known for a large vocal repertoire. The scientists found that they use a variety of calls and combinations of calls to interact with one another in specific situations. A combination of sounds known as “ABC calls”, for instance, means “watch out!”—the birds use them to warn each other of nearby predators such as a sparrowhawk. Another type of call know as the “D calls” mean “come over here,” a call the birds use after discovering a new source of food or when wanting their partner to come to the nest. But the birds often combine these two calls into so-called “ABC-D calls” when, for instance, the birds encounter predators and join forces to drive them away. When hearing a recording of these calls played in the natural order of ABC-D, the birds are alarmed and flock together, the scientists said. But the call ordering is artificially reversed to D-ABC, the birds don’t respond. “The results lead to a better understanding of the underlying factors in the evolution of syntax. Because the tits combine different calls, they are able to create new meaning with their limited vocabulary. That allows them to trigger different behavioral reactions and coordinate complex social interactions,” said Michael Griesser of the University of Zurich. He believes these factors may well have contributed to the development of language in humans. Last year, scientists also reported that a bird known as the chestnut-crowned babbler can rearrange meaningless sounds to create meaningful signals—also previously thought to be a uniquely human skill.