Birds’ Vocal Warnings Reveal a Global Link to Language Origins
ITHACA, N.Y. – A remarkable cross-continental discovery shows that more than two dozen bird species, spread across four continents, share a nearly identical whining vocal warning. The sound is produced when a parasite bird—such as a cuckoo—intrudes on a nest, and the host birds identify the threat and try to drive the intruder away. In a study led by researchers from Cornell University and the Donana Biological Station in Seville, Spain, this warning call appears to be a rare case of a vocalization that is learned from an innate response shared across multiple species. The findings are set to be published on October 3, 2025, in Nature Ecology and Evolution, and they illuminate how natural selection can shape the evolution of vocal communication systems across distant lineages.
The study is among the largest and most comprehensive investigations of brood parasitism to date, focusing on how hosts recognize and respond to parasites that lay eggs in their nests, often at the host’s expense. The researchers found that more than 20 different bird species, spanning continents from Australia to Africa and Asia, produce a nearly identical “whining” call when they spot a parasitic bird within their territory. This convergence raises compelling questions about how such a sound could emerge and persist across populations with no recent contact.
A Moment of Learning Within an Shared Innate Framework
When a bird hears the warning call, it instinctively moves to investigate the area for the parasite and potential threats to its nest. It is during this investigation, the team notes, that the birds begin absorbing cues from their surroundings—an aspect of social transmission. “It’s during this window of interaction that birds learn when to produce the sound in the future,” explains James Kennerley, co-lead author and a postdoctoral fellow at the Cornell Lab of Ornithology. The co-author adds that the vocalization sits at a fascinating midpoint: it is not a fully instinctive call nor a completely learned word, but a hybrid that can evolve with experience and environment.
Co-author Damián Blasi, a language scientist at Pompeu Fabra University in Spain, emphasizes the significance: “The call is a bridge between instinctive vocalizations we often see in animals and fully learned units like human words. It hints at how learned signals could emerge from innate calls, a possibility Charles Darwin first suggested.”
Working with fields in diverse habitats, the researchers observed that communities with more intricate networks of brood-parasite interactions tend to show stronger use of the whining call. As Kennerley notes, the value of cooperation is highlighted by this vocal cue: birds in affected regions may rely on shared signals to coordinate defense against parasites, thereby shaping patterns of collective behavior across species and landscapes.
<h2 Implications for the Study of Language and Communication
The findings challenge the traditional dichotomy between animal communication and human language. The authors propose that learned communication systems—like language in humans—may have evolved through gradual integration of instinctive and learned elements. In this case, natural selection appears to favor a signaling system that can be refined through social transmission while retaining a strong innate resonance. The discovery offers a tangible example of how evolution can endow species with learned meanings for sounds, potentially illuminating long-standing questions about the origins of language itself.
Beyond linguistics, the research underscores how a single ecological pressure—brood parasitism—can drive coordinated behavioral strategies across distant taxa. It also highlights the value of global collaboration in science, bringing together researchers from Europe, Africa, Asia, and the Americas to study how evolutionary forces shape communication at a fundamental level. The work signals that, in nature, learning and instinct are not opposing forces but complementary processes that together shape the way animals warn, cooperate, and adapt.
What Comes Next
As the full study undergoes peer review and broader publication, scientists expect to test whether other signaling systems in birds (and other animals) exhibit similar blends of innate triggers and social learning. The evolving story of how language origins may have roots in instinctive calls that acquire learned meaning continues to intrigue researchers, linguists, and evolutionary biologists alike.
