ArticlePloS one2026
The complex, graded vocal repertoire of the social Rüppell's vulture.
Article in PloS one, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The evolutionary origins of complex communication remain contentious, with social, ecological, and environmental factors proposed as selective drivers. The Social Complexity Hypothesis for Communicative Complexity (SCHCC) predicts that the cognitive demands of navigating socially intricate groups favour the evolution of complex communication. Although several studies provide support for the SCHCC, its empirical basis remains limited and inconsistent, as evidence is drawn predominantly from a small number of well-studied taxa (primarily primates), often neglects species' complete vocal repertoires, and employs inconsistent approaches for assessing social and vocal complexity. This narrow focus limits its generalisability across animals, underscoring the need to characterise the full communicative complexity of additional model species to expand its evolutionary relevance. Vultures, with their varied social structures, provide a unique system to test this hypothesis, yet foundational work on communication in this guild is limited. Here, we present the first quantitative analysis of the vocal repertoire of the critically endangered, highly social Rüppell's vulture, based on 2,500 calls recorded from two captive populations (35 individuals) across diverse social contexts. Using a fuzzy clustering approach, we reveal a repertoire far more complex than previously assumed, comprising multiple discrete and graded call types, with gradations likely conveying additional information. Calls serve diverse functions, including mediating parent-offspring interactions, manipulating conspecifics, and resolving conflicts. The Rüppell's vulture repertoire exceeds the average call repertoire size observed across birds and is likely an adaptation to this species' social life. Our results further establish vultures as a promising model for studying the vocal evolution and provide a framework for comparative analyses that can illuminate the selective pressures shaping complex communication.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.