Rüppell’s vultures use a wider range of calls than previously thought, study finds
Researchers analyzed 2,500 calls from 35 captive vultures and identified varied sounds associated with social interactions. Proposed breeding applications remain untested.
Rüppell’s vultures use a more varied range of calls than previously thought, according to a study published on October 21 in PLOS ONE. Researchers examined sounds made by captive birds at two Dutch zoos and found distinct and more gradually varying call types associated with social interactions. The findings could inform captive breeding, although the proposed applications have yet to be shown to improve outcomes.
What recordings revealed about Rüppell’s vulture calls
The team analyzed 2,500 calls from 35 Rüppell’s vultures in two captive populations. The birds were recorded in different social situations, and the researchers used a clustering method to examine similarities among their sounds. The paper describes both discrete call types and calls that vary by degree, with those variations potentially carrying additional information.
The authors associate the calls with interactions between parents and offspring, influencing other vultures and resolving conflicts. They report that the species’ repertoire exceeds the average number of call types observed across birds. Because the recordings came from captive populations, the findings do not establish how often wild Rüppell’s vultures use the same calls in the same circumstances.
Data collection took place from September 2024 to May 2025 at Diergaarde Blijdorp in Rotterdam and Vogelpark Avifauna in Alphen aan den Rijn. Utrecht University said Connor Proudfoot, working in Jorg Massen’s Vulture Cognition Lab, spent 150 hours recording the critically endangered species at the two colonies.
Why the calls matter for breeding and communication research
Utrecht University reported that chicks begin calling from inside their eggs two days before hatching. Proudfoot suggested that letting parents hear those calls could help prepare them when eggs are incubated artificially. He also proposed playing sounds made by mating pairs to see whether they encourage other pairs to breed. Those are potential uses of the findings, rather than demonstrated improvements to breeding success.
The study also bears on the idea that more socially complex species develop more complex communication. Its authors say evidence for that hypothesis remains limited and inconsistent, with much of the earlier work concentrated on primates. Vultures offer a comparison because their social structures vary, while their acoustic communication has received relatively little study. Earlier research identified at least 12 distinct calls in the griffon vulture, a closely related species, according to the paper.
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Sources and context
- 'Silent' vultures turn out to use a wide range of sounds to communicatePhys.org / Science X, reporting provided by Utrecht University
- The complex, graded vocal repertoire of the social Rüppell’s vulturePLOS ONE
- The complex, graded vocal repertoire of the social Rüppell’s vulture — Figure 1PLOS ONE
AI-assisted article checked against the listed sources. NewsJaws did not conduct interviews or attend the reported events.