It Takes All Kinds in Acoustic Communication: A New Perspective on the Song Overlapping Phenomenon

Over the last few decades, research into song overlapping produced many – often conflicting – interpretations of its function and culminated in the current debate about the usefulness of this concept. To avoid a deadlock in song overlapping research, we present a new approach to existing evidence and offer several novel hypotheses that might help enhance future experiments. Our analysis offers both a theoretical perspective and specific predictions of each testable hypothesis. We present a detailed analysis of important questions. First, what information does song overlapping convey (is it a signal of aggressive intent or of male quality)? Second, what evolutionary mechanism stabilizes honesty of song overlapping as a signal (is it an index signal, handicap, proximity risk, conventional signal or a modifier)? Additionally, we offer some alternative explanations of the phenomenon (song overlapping as a mask or an incidental phenomenon). We hope to encourage future researchers not only to gather high-quality experimental data, but also to make more careful interpretations, as we believe that no all-encompassing explanation of song overlapping will be formulated any time soon. Focused comparative approaches will be necessary, as song overlapping might have different functions in different species.