In this paper we review putative ecological variables that predict the occurrence of alarm calls by birds in the Australian arid zone. Signalling was common but use of signals is connected with number of food types, mobility and breeding system.
In prey species, it is often the case that individuals give alarms when they are threatened. In birds, such signals are frequently vocal signals that alert conspecifics to the presence of a threat. The responses to these calls by receivers may include fleeing to cover or approaching to mob the predator. Although most birds do give alarm calls when threatened, not all species do. We used Australian arid-zone bird species (n = 171) to test the hypothesis that alarm calling behaviour is determined by ecological, behavioural, and morphological characteristics. Eighty-nine percent of birds analysed possessed an alarm call, highlighting the prevalence of this behaviour. Our study found three variables – number of food types eaten, mobility, and breeding system – that were associated with predicting alarm calling behaviour in these species. The correspondence of alarm calling with these key life history attributes provides insight into benefits of having alarm calls and the evolutionary processes that have given rise to this behaviour.