Cooperatively breeding Arabian babblers call differently when mobbing in different predator-induced situations

Cooperatively breeding Arabian babblers (Turdoides squamiceps) have a reper toire of different calls that they use in predator-induced contexts. We inv estigated their vocal mobbing behavior in two different predator-induced si tuations. We presented territorial groups of babblers a perched, stuffed ow l representing an avian predator and a cat representing a ground predator B abblers approached in both situations and mobbed the predators with the sam e two call types. In both predator-induced situations their first call was a short, metallic-sounding "tzwick." In response to the cat, babblers conti nued to primarily use tzwicks. However, in continued response to the owl, t he babblers primarily used long trills. The experiments indicate that diffe rences in use of two common call types during mobbing provide information o n differences in predator-induced situations, although no call type per se identified a specific situation. The experiments suggest that die short tzw icks indicate a higher risk or urgency than trills and that combinations of both call types may provide graded information about differences in predat or-induced situations. The relatively stable groups of these cooperative br eeders might have favored evolution for using different calls in different mobbing situations.