Data from: Cooperative breeding influences the number and type of vocalizations in avian lineages

Although communicative complexity is often predicted to correlate with social complexity in animal societies, there has been a paucity of large-scale comparative analyses that test whether socially complex species have more complex systems of communication. I tested this social complexity hypothesis in birds (Class: Aves) due to the large amount of natural history information available for both vocal and social system in these species. To do so I marshalled data from primary and secondary records of avian vocal repertoires (N = 253), and for each of the species in the dataset I recorded the reported repertoire size and associated species information. Using phylogenetic comparative methods I find that cooperative breeding is a strong and repeatable predictor of vocal repertoire size while other social variables have little or no influence on repertoire size. Importantly, repertoire sizes expand concurrently with the evolution of cooperative breeding, suggesting a direct link between these two traits. Using the descriptions of vocalizations I demarcate how repertoires in cooperatively breeding species expand; specifically, cooperatively breeding species have significantly more contact calls and more alarm calls. Overall, these results therefore lend support to the hypothesis that social complexity via behavioral coordination leads to increases in vocal complexity.