Flight-call as species-specific signal in South American parrots and the effect of species relatedness in call similarity

Abstract

Vocal communication is fundamental to regulate the social interactions in most gregarious species and especially after dispersal movements for foraging or predator escape. A species common acoustic signal may be beneficial to group members and is especially critical in species that disperse over a large territory like parrots. In this study we investigate if parrots flight-calls carry species-specific characteristics and its variability within and across species. We also assess if the similarity between species flight-calls is influenced by phylogeny. We studied the flight-calls of 10 parrot species all occurring in Cerrado habitat in central Brazil. Our results show that, spectrum wise, there is not discrete spectral partition between species flight-calls. Flight-calls are conservative within most of the species. Both spectral and temporal dimensions contribute to the difference between species. The species specificity of the calls was confirmed by cross correlation approach. Nevertheless we found a difference in the call variability with some species presenting stereotyped calls (e.g. Amazona aestiva) while others presented variable calls (Brotogeris chiriri), suggesting that the function of the flight-call may differ between species, from convey species signatures to more specific information like group or individual signature. As expected closely related species have more similar calls. Overall, these result show that parrots flight-calls have species-specific characteristics. In some species these calls can potentially be used to maintain the group cohesion while in other species also code other type information enhancing that flight-calls may have different roles depending of the species life history.