Experimental test of the communicative value of syllable diversity and syllable switching in the common chiffchaff

Abstract

All songbirds have their own species-specific song, and vocal variety among individuals of the same species is used for communication. Some aspects of vocal variety have been shown to relate to sender characteristics and thus to convey a potential message to receivers. During playback experiments, individuals show different response patterns, which provide evidence for perception, and thus meaning, of the vocal variety. Here, we tested the impact of two types of vocal variety: syllable diversity and syllable switching in the common chiffchaff, Phylloscopus collybita , in two separate playback experiments. We found that syllable diversity was a relatively fixed trait and that variation among individuals was likely to reflect some male quality triggering responses of different intensity. Higher rates of syllable switching did not elicit different responses but songs after playback showed that it is a dynamic trait, potentially contributing to motivational signalling together with other song parameters. The resolution of analyses in our experiments revealed subtle changes in vocal features over time in unprecedented detail. This approach unveiled an intricate combination of various vocal features during the response that may complement each other during vocal interactions. We believe future studies would benefit from the same resolution, through which one can explore advanced levels in animal communication. • Syllable diversity is likely to be a fixed trait signalling male quality. • Syllable switching may be a dynamic trait related to motivation. • Birdsong is highly dynamic during vocal interactions. • Some parameters follow opposite patterns during vocal interactions. • Studying behaviour at high temporal resolution offers advanced insights.