Bioacoustics The International Journal of Animal Sound and its Recording, 2011, Vol. 20, pp. 235–250 © 2011 AB Academic Publishers SEX DISCRIMINATION AND MATE RECOGNITION BY VOICE IN THE YELKOUAN SHEARWATER PUFFINUS YELKOUAN CHARLOTTE CURÉ 1*2,3 , THIERRY AUBIN 1,3 AND NICOLAS MATHEVON 2,3 1 Université Paris-Sud, Equipe Communications acoustiques animales, CNPS, CNRS UMR 8195, France. 2 Université de Saint-Etienne, Equipe Neuro-Ethologie Sensorielle, CNPS, CNRS UMR 8195, France. 3 Centre National de la Recherche Scientiique, Centre de Neurosciences Paris-Sud, UMR 8195, France ABSTRACT Shearwaters are nocturnal seabirds that rely on olfaction and acoustics to communicate at night. Although previous studies have described the vocal repertoire of some shearwater species, there is a need for more precise experimental data investigating the biological relevance of these acoustic signals in this seabird group. The present paper focuses on the vocal behaviour of the Yelkouan shearwater Pufinus yelkouan, a poorly studied species which produces a single major call composed of two notes, a noisy note and a clear one. A quantitative analysis of the calls allowed to extract the acoustic parameters supporting both sexual and individual signatures. Playback experiments were conducted during the incubation period to test the ability of the Yelkouan shearwater (1) to vocally identify the sex of the emitter, and (2) to discriminate the mate from a non-mate. We showed that birds discriminate the sex of the emitter, calling back almost exclusively to calls of birds of the same sex. Among the few birds replying to calls of the opposite sex, females responded to calls of their partner only, whereas males responded equally to calls of the partner or to calls of a non-partner, suggesting that females are vocally more selective than males. Key words: acoustic communication, sex discrimination, mate recognition, seabirds, shearwaters. INTRODUCTION Species belonging to the Procellariidae family (fulmars, gadly petrels, prions, and shearwaters), as most seabirds, breed on seashores in large colonies, a way of life which leads to a fair amount of interactions amongst individuals (Del Hoyo et al. 1992). Moreover and like many seabirds, these birds are monogamous species, showing an inter- annual idelity to their nest site and to their mate (Bradley et al. *Corresponding author, Charlotte Curé: Email: cc201@st-andrews.ac.uk