Birds’ Vocal Warnings Provide New Insight Into the Origins of Language

October 3, 2025

Ithaca, N.Y.—An international team of researchers discovered that birds separated by vast geographic distances—and separated by millions of years of evolution—share a remarkably similar learned vocal warning to identify parasitic enemies near their nests. 

The findings, published today in the journal Nature Ecology and Evolution, provide a glimpse into the role natural selection can play in the evolution of vocal communication systems. The study, led by researchers at Cornell University and Donana Biological Station in Seville, Spain and more than a dozen institutions, is one of the largest and most comprehensive studies concerning brood parasites to date. 

The researchers found that more than 20 different bird species across four continents produce nearly identical “whining” vocalizations when they spot a parasitic bird in their territory. Parasitic birds, such as cuckoos, lay their eggs in other species’ nests, forcing the host to raise their young, often at the expense of their own offspring. It is therefore advantageous for the host species to identify the nest parasites and seek to prevent the parasites from laying eggs in their nests. 

But, the researchers wondered why birds from locations spanning Australia, China and Zambia all use the same call to identify their parasites, despite never coming into contact with each other. 

To test this question, the researchers used playback experiments to assess how hosts responded to hearing whining calls compared to other vocalizations and used model presentation experiments to assess how individuals responded to seeing a cuckoo compared to seeing predators and non-predators.  

The results of the experiments represent the first known example of an animal vocalization that is learned from an innate response that is shared across multiple species.

When a bird hears the whining call, even if the call is coming from different species on different continents, they instinctively come to investigate what is happening, that’s when according to the research the birds start absorbing the cues around them, what Damián Blasi, co-author of the study and a language scientist at Pompeu Fabra University, Spain calls social transmission. 

“It’s then, when birds are absorbing the clues around them, that the bird learns when to produce the sound in the future,” said James Kennerley, co-lead author and postdoctoral fellow at the Cornell Lab of Ornithology. 

“The fascinating thing about this call is that it represents a mid-point between the instinctive vocalizations we often see in animals and fully learned vocal units like human words,” said William Feeney, an evolutionary ecologist and co-lead author of the study from Donana Biological Station in Seville, Spain.

The research also revealed that species which produce the whining call tend to live in areas with complex networks of interactions between nest parasites and their hosts. “With birds working together to drive parasites away, communicating how and when to cooperate is really important so this call is popping up in parts of the world where species are most affected by brood parasitism” said Kennerley. The result, said Kennerley, “is that the evolution of the whining vocalization is affecting patterns of cooperative behaviors between birds around the world.”

The link between the innate whining sound and the learned response by the bird is what the authors said makes this study unique. “For the first time, we’ve documented a vocalization that has both learned and innate components, potentially showing how learned signals may have evolved from innate calls in a way first suggested by Darwin,” said Feeney. “It’s like seeing how evolution can enable species to give learned meanings to sounds.”

The findings challenge long-held assumptions about the sharp division between animal communication systems and human language. The authors suggest that learned communication systems, like human language, may have evolved through the gradual integration of instinctive and learned elements.

####

Reference: Feeney, W. E., J. A. Kennerley, D. Wheatcroft. W. Liang, J. B. Lamb, N. Teunissen, S. L. Lawson, J. K. Enos, B. Zhou, C. Poje, N. M. Richardson, T. A. Ryan, Z. Cowan, R. M. Brooker, M. Attwood, J. Boersma, M. Zamora, A. Attisano, R. Gula, J. Theuerkauf, R. Gloag, V. D. Fiorini, S. A. Gill, A. Peters, M. Honza, C. N. Spottiswoode, M. E. Hauber, A. Manica, M. S. Webster, D. E. Blasi. (2025). Learned use of an innate sound-meaning association in birds. Nature Ecology and Evolution. https://doi.org/10.1038/s41559-025-02855-9

Funding: 

This work was supported by the Alexander von Humboldt Foundation (WEF and MEH), Birds Queensland (WEF and MSW), the British Trust for Ornithology (WEF), the Hermon-Slade Foundation (#HS15/1 to WEF), an Edward W. Rose Postdoctoral Fellowship in the Cornell Lab of Ornithology for part of this work (JAK), and the US National Science Foundation (#1353681 to MSW, #1953226 to MEH and #1952726 to SAG).

Editors: Download images. The use of this material is protected by copyright. Use is permitted only within stories about the content of this release. Redistribution or any other use is prohibited without express written permission of the Cornell Lab of Ornithology or the copyright owner.