Calling rhythm as a predictor of the outcome of vocal interactions: flight decisions in pale-winged starling pairs
Abstract
Vocal communication plays an important role in the regulation of social interactions and in the coordination of activities. Synchrony is an essential part of the establishment and maintenance of pair bonds but few studies investigate decision taking at the pair level. We investigated whether characteristics of the call exchanges that precede flight in the pale-winged starling (Onychognathus nabouroup) predict if one, two or none of the pair members depart. The analysis of 61 interactions revealed that the overall rhythm of the call exchange as well as acceleration towards the end of the interaction were highly predictive of the outcome. Faster rhythms were associated with a higher probability of departure by one or both birds. Solitary birds showed no acceleration in calling. These findings match earlier studies showing that higher rates of alarm calling indicate imminent departure, and highlight the relationship between temporal features of vocal interactions and their outcome.