VOCAL-POSTURAL COORDINATION OF A SEXUALLY DIMORPHIC DISPLAY IN A MONOMORPHIC SPECIES - THE BARBARY-DOVE

In the Barbary dove (Streptopelia risoria L.), communication involves visual and vocal signals. In this species, behavioural interaction bet ween sexual partners leads to changes in the reproductive hormonal con dition of both sexes. At the beginning of courtship, male doves perfor m the bowing display. This display is composed of a stereotyped moveme nt pattern (bowing) combined with an acoustic pattern (bow-call). In t his paper, we studied the individual temporal patterning of bowing and the bow-call and how they are integrated in the display. The co-ordin ation between bowing movements and bow-call was analysed using a digit al system for the synchronous analysis of acoustic-visual signals. Bow -calls differ between individuals in both temporal and frequency chara cteristics, and in their repetition rate. The bowing movements do not differ between individuals in their temporal structure but the repetit ion rate is individually different. The repetition rates of the vocal and postural motor patterns are highly correlated. However, the two si gnals are not synchronised and the phase delay between them is individ ually different. We suggest that in the bowing display the gender and the identity are signalled respectively by the bowing pattern and the bow-call. The integration of the two signals generates a third signal, the integrated bowing display rate. The role of the three signals dur ing male-male encounters and during courtship behaviour is discussed.