Communication in the Third Dimension: Song Perch Height of Rivals Affects Singing Response in Nightingales

Philipp Sprau,Tobias Roth,Marc Naguib,Valentin Amrhein,Robert Planque

doi:10.1371/journal.pone.0032194

Philipp Sprau, Tobias Roth + Show 3 more

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https://doi.org/10.1371/journal.pone.0032194

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Abstract

Many animals use long-range signals to compete over mates and resources. Optimal transmission can be achieved by choosing efficient signals, or by choosing adequate signalling perches and song posts. High signalling perches benefit sound transmission and reception, but may be more risky due to exposure to airborne predators. Perch height could thus reflect male quality, with individuals signalling at higher perches appearing as more threatening to rivals. Using playbacks on nightingales (Luscinia megarhynchos), we simulated rivals singing at the same height as residents, or singing three metres higher. Surprisingly, residents increased song output stronger, and, varying with future pairing success, overlapped more songs of the playback when rivals were singing at the same height than when they were singing higher. Other than expected, rivals singing at the same height may thus be experienced as more threatening than rivals singing at higher perches. Our study provides new evidence that territorial animals integrate information on signalling height and thus on vertical cues in their assessment of rivals.

Highlights

IntroductionLong-range signals such as the song of songbirds can encode information about signaller quality, condition and motivation [1]
In animal communication, information is often exchanged over long distances
When rivals were simulated as singing from high perches, males showed a similar song output during playback as compared to before playback (Fig. 1a)

Summary

Introduction

Long-range signals such as the song of songbirds can encode information about signaller quality, condition and motivation [1]. Such information can be encoded in the spatial behaviour of signallers. The location of nonmoving rivals within [5] and outside [6] the territory boundaries has been shown to influence territory defence behaviour of residents. Spatial movements of rivals can affect territorial behaviour of resident males [7,8] and of neighbours [9], highlighting the importance of spatial cues in communication

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