Song performance improves with continued singing across the morning in a songbird

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Vocal performance – an animal's ability to produce physically challenging vocalizations – can reflect a signaller's overall condition and can be a reliable signal of quality. It has been suggested recently that songbirds improve vocal performance through recent practice during intense dawn singing. We tested whether recent practice improves vocal performance in swamp sparrows, Melospiza georgiana, a species for which the biomechanical constraints and biological implications of vocal performance are well established. We measured vocal deviation – a measure of performance – in 1527 songs recorded from 11 captive swamp sparrows, four of which were developmentally stressed as juveniles. Vocal performance improved across the morning as a function of both the cumulative number of songs previously performed and the time of day. Song types with introductory syllables showed greater improvement than more typical song types composed solely of trilled syllables, and across all song types, as song output increased, the average improvement in vocal performance also increased. However, males with high song output exhibited greater variability in vocal performance, suggesting that some individuals might experience fatigue in song production. Furthermore, birds that had been developmentally stressed as juveniles showed greater improvement over the morning than birds that were not stressed. If conspecifics attend to within-individual variation in vocal performance, then improvement in vocal performance over the course of a day may drive birds to sing early and often, although fatigue may limit the extent to which this advantage may be gained.





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Dinh, JP, S Peters and S Nowicki (2020). Song performance improves with continued singing across the morning in a songbird. Animal Behaviour, 167. pp. 127–137. 10.1016/j.anbehav.2020.06.018 Retrieved from

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Stephen Nowicki

Professor of Biology

Our lab studies animal communication, asking both proximate and ultimate questions about how signaling systems function and how they evolve. Most of our work is done with birds, although lab members have studied a variety of other taxa. One major theme that runs through our work is to understand how signal reliability (“honesty”) is maintained in the face of the competing evolutionary interests of signal senders and receivers. We use both laboratory experiments and field-based analyses to test hypotheses about the costs of signal production, which theory suggests are necessary to maintain reliability. For example, we have demonstrated that the reliability of birdsong as a signal of quality in the context of mate choice is maintained by variation in the response of young birds to early developmental stress, which in turn affects brain development and song learning. Another theme that runs through our work concerns how animals themselves perceive signals, in particular the role of categorical perception in communication. Our work here began with birdsong, for example demonstrating context-dependent variation in category boundaries that define the smallest acoustic units of song (“notes”), and identifying categorical responses of neurons in the “song system” of the brain to variation in those notes. More recently, we have begun to study categorical perception in visual signaling, demonstrating for example that the carotenoid-based orange-red coloration commonly used in assessment signaling may be perceived categorically. This finding illustrates the connection between our interests in perception and reliability, given that canonical models of reliability assume continuous perception.

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