Vocal athletics-from birdsong production mechanisms to sexy songs

Birdsong is an important signal used in intra-and intersexual communication in a reproductive context. Strong sexual and natural selective forces act on this behaviour, such that singing individuals can be viewed as vocal athletes whose performance is critical for reproductive success. In this review, I argue and illustrate how a solid understanding of song production mechanisms can enhance our investigations of performance. From a production perspective, temporal and spectral features of song are relatively well understood and therefore are discussed in detail. Performance ranges of temporal and frequency characteristics can be broad, but often involve different production mechanisms, with different constraints and trade-offs underlying their generation. Based on these multifaceted features, I argue that song may be perceived as an 'acoustic gestalt', which for each syllable represents a specific location in a complex multidimensional parameter space characterized by differential contributions of individual features. Derived from this view, I also propose that individual males may be showing specialization for exceptional performance of some, but not all, features of song. To illustrate this possibility for a future research focus, I quantify some song features of seven male European robins, and, although the data set is limited, it shows that different individuals exhibit different performance levels across a number of song features. (c) 2021 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Automated summary

Birdsong is a crucial signal in reproductive communication, with individual performance impacting reproductive success. Understanding the mechanisms of song production can enhance investigations of performance. Different individuals exhibit varying performance levels in different song features, suggesting specialization in certain aspects of song.