Captive Rüppell’s vultures display extensive, graded vocal repertoires

A peer-reviewed observational study reports that Rüppell’s vultures produce an extensive, graded vocal repertoire, with calls recorded from eggs, chicks and adults in captive settings. Published in PLOS One as “The complex, graded vocal repertoire of the social Rüppell’s vulture,” the study characterizes the species as highly social and proposes that this lifestyle might help explain the variety of its vocalizations. The authors present the social explanation as a possibility rather than a tested cause, and the observations were confined to birds at two Dutch institutions rather than free-ranging populations.

Researchers collected data from September 2024 to May 2025 at Vogelpark Avifauna and Diergaarde Blijdorp in the Netherlands. A camera-and-microphone system mounted on a tripod documented general group activity and feeding. A separate nest microphone enabled passive monitoring of parent–chick vocalizations in nest 3, while the incubation-room setup captured vocalizations associated with the hatching process.

Other recordings were obtained during veterinary procedures, including a one-month-old chick being ringed and weighed. These approaches placed microphones in different settings, allowing the study to cover developmental stages and contexts ranging from close handling to group activity and caregiving. The recordings included pre-hatching vocalizations from an internally pipped egg identified as 25G4.

The researchers also recorded the same chick at one month of age during a veterinary procedure, as well as a nest-camera sequence showing its mother, Ayla, feeding it. Chick 25G15 was recorded in the incubation room one day after hatching and while breaking through the shell of its egg. Together, the material documents vocal behavior across egg, chick and adult stages and includes both direct vocalizations and recorded interactions such as parent–chick exchanges, group activity and feeding.

The central result is that Rüppell’s vulture vocalizations form a complex repertoire with graded variation. The research frames the species’ social behavior—group living, feeding interactions and parent–chick communication—as a possible factor contributing to that complexity, but the captive observational design does not establish why the repertoire developed or whether the same patterns occur throughout wild populations. Its contribution is therefore a detailed characterization of calls and call contexts using complementary recording methods across the early life cycle.

Because the observations came from particular birds at two institutions, the findings should be interpreted as evidence about the repertoire documented in those settings rather than a complete census of Rüppell’s vulture vocal behavior in nature.

Subject of Research: Vocal repertoire and social behavior in captive Rüppell’s vultures

Article Title: Rüppell’s vultures have an impressively extensive vocal repertoire, which might be driven by the highly social behavior of this critically endangered species

Article References: Rüppell’s vultures have an impressively extensive vocal repertoire, which might be driven by the highly social behavior of this critically endangered species. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: Rüppell’s vulture, vocal repertoire, animal communication, bioacoustics, social behavior, parent–chick communication, captive birds, conservation, PLOS One, ppell, vultures, impressively