Functional traits including interspecific sociality affect mobbing behaviour in a bird community of southern China

Mobbing is a prevalent anti-predatory behaviour in birds where prey actively engage in harassing predators. Functional traits have been shown to affect prey species' tendency to engage in mobbing, but empirical studies have largely neglected to assess the influence of some other potentially important functional traits, such as intraspecific and interspecific sociality, on mobbing or measured different aspects of the behaviour. In this study, we performed playback experiments that elicited mobbing responses from a forest bird community in southern China, to investigate the influence of body mass, foraging strata, as well as intra- and interspecific sociality, on the prevalence of mobbing, as well as the intensity of aggression and vocalness. We found that species with small body masses engaged in more frequent and intense mobbing behaviours. Notably, interspecific sociality was negatively associated with birds' mobbing prevalence and tended to be negatively associated with vocalness.