Signalling through acoustic windows: nightingales avoid interspecific competition by short-term adjustment of song timing
The function of bird song is closely linked to sexual selection through female choice and male–male competition, and thus variation in communication success is likely to have major fitness consequences for a singing male. A crucial constraint on signal transmission is imposed by background noise, which may include songs from other species. I investigated whether singing nightingales (Luscinia megarhynchos) avoid temporal overlap with the songs of other bird species in a playback experiment. I analysed the temporal song patterns of six males, each of which were exposed to songs of other species. The nightingales significantly avoided overlapping their songs with the playback songs, and started singing preferentially during the silent intervals between the heterospecific songs. This timing of song onset produced a greater variability in pause duration compared to the nightingales’ undisturbed solo singing. These findings suggest that birds adjust their song timing to avoid acoustic interference on short temporal scales, and thus are able to improve the efficiency of acoustic communication in complex sonic environments. Moreover, the results indicate that temporal song patterns can be affected by the songs of other species, and thus such influences should be taken into account when studying bird song in the field.
KeywordsAnimal communication Acoustic masking Bird song Luscinia megarhynchos Noise
Several students and members of staff of the Behavioural Biology Group at the Freie Universität Berlin provided skilful help with the handrearing. The research group was generally supervised by Dietmar Todt and Henrike Hultsch, and funding was provided by the German Research Foundation (award To 13/30-1). Many thanks are due to Tina Sommer and Christoph Lange, who shared their song recordings with me, and to Nigel Mann for the nightingale drawing used in Fig. 2. Furthermore, I am most grateful to Luke Rendell for coding the randomisation tests. He, Peter Slater, and two anonymous referees gave helpful comments on the manuscript which were much appreciated. While analysing the data and writing the manuscript I was supported by an Emmy Noether fellowship from the German Research Foundation (award Br 2309/2-1). The experiments described in this study comply with the “Principles of animal care”, publication No. 86-23, revised 1985 of the National Institute of Health, and also with the current laws of the Federal Republic of Germany.
- Brumm H, Slabbekoorn H (2005) Acoustic communication in noise. Adv Study Behav 35:151–209Google Scholar
- Catchpole CK, Slater PJB (1995) Bird song: biological themes and variations. University Press, CambridgeGoogle Scholar
- Ficken RW, Popp JW, Matthiae PE (1985) Avoidance of acoustic interference by Ovenbirds. Wilson Bull 97:569–571Google Scholar
- Gerhardt HC, Huber F (2002) Acoustic communication in insects and anurans. University of Chicago Press, ChicagoGoogle Scholar
- Gochfeld M (1978) Intraspecific social stimulation and temporal displacement of song of the lesser sky lark Alauda gugula. Z Tierpsychol 48:337–355Google Scholar
- Greenfield MD (2005) Mechanisms and evolution of communal sexual displays in arthropods and anurans. Adv Study Behav 35:1–62Google Scholar
- Klump GM (1996) Bird communication in the noisy world. In: Kroodsma DE, Miller EH (eds) Ecology and evolution of acoustic communication in birds. Cornell University Press, Ithaca, pp 321–338Google Scholar
- Popp JW, Ficken RW (1987) Effects of non-specific singing on the song of the ovenbird. Bird Behav 7:22–26Google Scholar
- Popp JW, Ficken RW, Reinartz JA (1985) Short-term temporal avoidance of interspecific acoustic interference among forest birds. Auk 102:744–748Google Scholar
- Schroeder DJ, Wiley RH (1983) Communication with shared song themes in tufted titmice. Auk 100:414–424Google Scholar
- Todt D, Hultsch H (1998) Hierarchical learning, development and representation of song. In: Balda RP, Pepperberg IM, Kamil AC (eds) Animal cognition in nature. Academic, San Diego, pp 275–303Google Scholar