The Hazel Grouse (Bonasa bonasia), a sedentary bird species belonging to the grouse family, breeds across northern Eurasia, central and eastern Europe in dense, mixed coniferous woodland. While the territorial call is a good indicator of the grouse's presence, the role of acoustic cues is not clear. This study aimed to assess acoustic characteristic of the Hazel Grouse call and differences between sexes. Recording and playback experiments were performed in Alpes-de-Haute-Provence (France). The territorial calls of males (n=8) and females (n=5) were recorded in the field. Analyses of signals show that the male has a high-pitched ti-ti-ti-ti-ti call, and the female a liquid tettettettettet call. The frequency of the peak of maximum amplitude of calls was very high for such a large bird: 6841Hz ±786 for the male and 6034Hz ±476 for the female. After careful analyses, it turns out that the whole spectrum of the call was within the audible domain. Moreover, within-individual variability, that allows encoding of the individual identity, is higher in males (Cvb/Cvi=2.28) than in females (Cvb/Cvi<0.01). The particularity of producing such high frequency calls may reflect the necessity to improve localization efficiency in dense woodland, as high frequencies are associated to a better directionality. Moreover our results suggest that acoustic characteristics of male calls have sufficient inter-individual variability to allow the coding of individual identity.