The imitation dilemma: can parrots maintain their vocal individuality when imitating conspecifics?

Abstract

Abstract Many species of parrots live in fission–fusion social systems, characterised by frequent changes in flock composition. In these systems, the ability to selectively choose flock members is essential in order to maximise individual fitness. As a result, most species of parrots have individual distinctive contact calls that mediate the formation of groups during fission and fusion events. However, in vocal interactions during fission and fusion events, individuals will modify the fine-scale structure of their contact calls in a manner that sometimes will result in imitation of the contact calls of another individual, potentially altering or weakening the individual distinctiveness of contact calls. This presents parrots with an interesting dilemma. Here we present a study investigating the effect of vocal modification during interactions, including vocal imitation, on the individual distinctiveness and sex-specific differences of contact calls from ten captive bred peach-fronted conures (Eupsittula aurea). In order to determine if vocal individual- and sex distinctiveness persists in contact calls that are modified to that of another individual, we compared nine acoustic parameters from spontaneous (baseline) contact calls and contact calls emitted as response to a playback stimulus. Although modified, all acoustic parameters remained individually distinctive when the focal individuals interacted with the playback stimulus. These results provide a strong basis for discriminating between calls from different individuals across several social contexts, which could play an important role in mediating selective associations between individual peach-fronted conures during fission and fusion events.