Raven food calls indicate sender's age and sex.

Send to Front Zool. 2018 Mar 13;15:5. doi: 10.1186/s12983-018-0255-z. eCollection 2018. Boeckle M1,2,3, Szipl G1,2, Bugnyar T1,2. Author information 1 1Department of Cognitive Biology, University of Vienna, Vienna, Austria. 2 2Konrad Lorenz Forschungsstelle, Core Facility, University of Vienna, Gruenau im Almtal, Austria. 3 3Department of Psychology, University of Cambridge, Cambridge, UK. Abstract BACKGROUND: Acoustic parameters of animal signals have been shown to correlate with various phenotypic characteristics of the sender. These acoustic characteristics can be learned and categorized and thus are a basis for perceivers' recognition abilities. One of the most demanding capacities is individual recognition, achievable only after repeated interactions with the same individual. Still, class-level recognition might be potentially important to perceivers who have not previously encountered callers but can classify unknown individuals according to the already learned categories. Especially for species with high fission-fusion dynamics that repeatedly encounter unknown individuals it may be advantageous to develop class-level recognition. We tested whether frequency-, temporal-, and amplitude-related acoustic parameters of vocalizations emitted by ravens, a species showing high fission-fusion dynamics in non-breeder aggregations, are connected to phenotypic characteristics and thus have the potential for class-level recognition. RESULTS: The analysis of 418 food calls revealed that some components summarizing acoustic parameters were differentiated by age-classes and sex. CONCLUSIONS: Together, the results provide evidence for the co-variation of vocal characteristics and respective sex and age categories, a prerequisite for class-level recognition in perceivers. Perceivers that are ignorant of the caller's identity can thus potentially recognize these class-level differences for decision-making processes in feeding contexts. KEYWORDS: Acoustic characteristics; Age; Bioacoustics; Call production; Corvid; Corvus corax; Food call; Raven; Sex; Vocalization PMID: 29563949 PMCID: PMC5848575 DOI: 10.1186/s12983-018-0255-z Free PMC Article https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/29563949/