Skylarks (Alauda arvensis) increase their duty cycle in a territorial context

Nicole Geberzahn , Thierry Aubin

Birdsong usually serves to attract mates and to repel territorial rivals and is often produced by males only. During territorial conflicts song may provide information on the signaller’s physical strength, and on its motivation to fight. Males may vary aspects of their singing behaviour when engaged in territorial interactions, and such variation may be an honest signal of certain traits of the signaller such as body size, condition or motivation. This information may be used by receivers in territorial decisions. We studied contextual variation in the song of skylarks, Alauda arvensis, a songbird with a large vocal repertoire and a continuous and versatile singing style. We challenged subjects with simulated territorial intrusions by broadcasting conspecific song and recorded their vocal responses. When challenged, males increased their duty cycle. Duty cycle was calculated by subtracting all silent pauses within a song (inter-syllable pauses) and dividing the remaining ‘on-song-time’ by the total song duration. We found no contextual variation in other acoustic parameters (pitch, syllable and inter-syllable duration, song rate and song versatility). Duty cycle might be an honest signal for the competitive ability and might be perceived as such by skylarks - this hypothesis will be tested in the future.

Mots clés: birdsong; territorial function; contextual variation; skylark

Domaines: Acoustique [physics.class-ph]

Nicole Geberzahn, Thierry Aubin. Skylarks (Alauda arvensis) increase their duty cycle in a territorial context. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810558⟩