Do Birds Have Language?

In our quest to find what makes humans unique, we often compare ourselves with our closest relatives: the great apes. But when it comes to understanding the quintessentially human capacity for language, scientists are finding that the most tantalizing clues lay farther afield.

Human language is made possible by an impressive aptitude for vocal learning. Infants hear sounds and words, form memories of them, and later try to produce those sounds, improving as they grow up. Most animals cannot learn to imitate sounds at all. Though nonhuman primates can learn how to use innate vocalizations in new ways, they don’t show a similar ability to learn new calls. Interestingly, a small number of more distant mammal species, including dolphins and bats, do have this capacity. But among the scattering of nonhuman vocal learners across the branches of the bush of life, the most impressive are birds — hands (wings?) down.

Parrots, songbirds and hummingbirds all learn new vocalizations. The calls and songs of some species in these groups appear to have even more in common with human language, such as conveying information intentionally and using simple forms of some of the elements of human language such as phonology, semantics and syntax. And the similarities run deeper, including analogous brain structures that are not shared by species without vocal learning.

These parallels have motivated an explosion of research in recent decades, says ethologist Julia Hyland Bruno of Columbia University, who studies social aspects of song learning in zebra finches. “Lots of people have made analogies between language and birdsong,” she says.

Hyland Bruno studies zebra finches because they are more social than most migratory birds — they like to travel in small bands that occasionally gather into larger groups. “I’m interested in how it is that they learn their culturally transmitted vocalizations in these groups,” says Hyland Bruno, coauthor of a paper in the 2021 Annual Review of Linguistics comparing birdsong learning and culture with human language.

Both birdsong and language are passed culturally to later generations through vocal learning. Geographically distant populations of the same bird species can make small tweaks to their songs over time, eventually resulting in a new dialect — a process similar in some ways to how humans develop different accents, dialects and languages.

With all these similarities in mind, it’s reasonable to ask if birds themselves have language. It may come down to how you define it.

“I wouldn’t say they have language in the way linguistic experts define it,” says neuroscientist Erich Jarvis of the Rockefeller University in New York City, and a coauthor of Hyland Bruno’s paper on birdsong and language. But for scientists like Jarvis who study the neurobiology of vocal communication in birds, “I would say they have a remnant or a rudimentary form of what we might call spoken language.

Read more: Smithsonian Magazine

Can these birds explain how language first evolved?

If you want a no-fuss, no-muss pet, consider the Bengalese finch. Dubbed the society finch for its friendliness, breeders often use it to foster unrelated chicks. But put the piebald songbird next to its wild ancestor, the white-rumped munia, and you can both see and hear the differences: The aggressive munia tends to be darker and whistles a scratchy, off-kilter tune, whereas the pet finch warbles a melody so complex that even nonmusicians may wonder how this caged bird learned to sing.

All this makes the domesticated and wild birds a perfect natural experiment to help explore an upstart proposal about human evolution: that the building blocks of language are a byproduct of brain alterations that arose when natural selection favored cooperation among early humans. According to this hypothesis, skills such as learning complex calls, combining vocalizations, and simply knowing when another creature wants to communicate all came about as a consequence of pro-social traits like kindness. If so, domesticated animals, which are bred to be good-natured, might exhibit such communication skills too.

The idea is rooted in a much older one: that humans tamed themselves. This self-domestication hypothesis, which got its start with Charles Darwin, says that when early humans started to prefer cooperative friends and mates to aggressive ones, they essentially domesticated themselves. Along with tameness came evolutionary changes seen in other domesticated mammals—smoother brows, shorter faces, and more feminized features—thanks in part to lower levels of circulating androgens (such as testosterone) that tend to promote aggression.

Higher levels of neurohormones such as serotonin were also part of the domestication package. Such pro-social hormones help us infer others’ mental states, learn through joint attention, and even link objects and labels—all prerequisites for language, says developmental psychologist Michael Tomasello of Duke University in Durham, North Carolina, who studies social cognition.

In recent papers and at Evolang, a biannual conference on language evolution held here this spring, researchers turned to birds, foxes, and bonobos to help understand how domestication may have paved the way for language. Constantina Theofanopoulou, a neuroscientist at the University of Barcelona in Spain who convened the Evolang workshop, calls it the “most promising” working hypothesis to account for the thorny problem of language evolution, because it “puts together evidence from different levels of biological analysis: the anatomical, the brain, the endocrine system, and behavior.”

Read more: Science

These birds use a linguistic rule thought to be unique to humans

When it comes to human language, syntax — the set of rules for arranging words and phrases to impart meaning — is important. People might understand what you meant if you declared “to the store I go must,” but your phrasing wouldn’t seem quite right. And saying “must store go the I to” wouldn’t get you anywhere at all, even though the same six short words were in play.

But sometimes we use syntax to impart complex combinations of ideas. “Careful, it’s dangerous” is a phrase that has meaning, and so is “come toward me.” When those two phrases are combined, they have a different meaning than they do on their own: They’re directing the receiver to act in a different way than either phrase would independently.

Until now, only humans seemed to use syntax this way. But a study published Tuesday in Nature Communications suggests that the Japanese great tit — a bird closely related to the North American chickadee — uses grammatical rules like these in its calls.

Read more: Washington Post