Yellow warbler, one of 21 species studied
A bird also cries: first evidence of attributing meaning to sounds shows that Darwin’s speculation may be right.
A study on October 3 in Nature Ecology & Evolution suggests that evolution may have influenced the development of vocal language, after discovering that birds from different parts of the world “complain” in practically the same way when they encounter parasitic species.
The international investigation is the first ever to demonstrate a known case of animal vocalization learned from an innate response.
The team analyzed 21 species of birds from four continents and looked at the parasitism of their litters. Parasitism is a recurring practice of more than 300 species, which deposit their eggs in the nest of another species to force them to create offspring that are not biologically theirs.
The birds studied lived in habitats in Australia, China and Zambia, and had no contact with each other. But curiously, they almost all emitted similar vocalizations when they detected parasitic birds in their areas.
Upon hearing the ‘calls for help’, other birds approached to investigate: they learned not only to recognize, but also to reproduce the same sound. And the call is emerging in parts of the world where species are most affected by brood parasitism.
The authors believe that this behavior could provide new clues about the origin of human language: the signals we emit are learned, but from innate and natural vocalizations, as speculated by Charles Darwin.
“It’s like seeing how evolution can allow species to attribute learned meanings to sounds,” says study co-leader William Feeney, from the Doñana Biological Station, in Spain, cited by the magazine.
