In European quail, individual birds can be discriminated by using only three parameters describing the long-distance vocalizations used during pair bonding. In the male vibrato these parameters are: the total duration of the vibrato, the duration of the second syllable and the highest energy component of the fundamental. For the male triplet, the necessary parameters are: the interval between the highest frequency points of syllables 1 and 2, of syllables 2 and 3, and the frequency of the inflexion point of the third syllable. Individual females can usually be identified by three rally call parameters; these being the interval between syllables 1 and 2, the interval between the lowest frequency points, and the frequency of maximal amplitude in the second syllable of the rally call. Comparison based on these three parameters for each form of vocalization showed that more than 80% of individuals were correctly discriminated thus permitting fairly reliable counts of populations in the field. Intra-individual variations of parameters of male triplets linked with sexual development or age could permit sexual selection of singing males by females. Comparisons between the sexual calls of the European quail and the Grey partridge lead to evolutionary suggestions about the structure of vocalizations in these two related sympatric species.