Timing of incubation bouts by ring doves (Streptopelia risoria).

Ring dove parents share in incubation and brooding such that the male sits for a block of time toward the middle of the day and the female sits the rest of the time. In order to evaluate the role of the sexes in determining nest exchange, approaches to the nest, the timing of incubation behavior, and the topography of interactions at the nest site were continuously monitored. Most nest exchanges (87%) were initiated by the nonsitting mate. There was less variability associated with the onset of sitting by the female than by the male. The male entered the nest area repeatedly from the time of lights-on until nest exchange several hours later. In contrast, the female rarely entered the nest area when the male was sitting, and when she did approach, nest exchange usually ensued. When the male's entrances to the nest area were prevented until the usual time of nest exchange, the timing of the subsequent sitting bout and nest exchange was not altered, which indicates that male visits are not a necessary prerequisite for nest exchange. Each pair developed a cooperative interaction as incubation progressed. When mates were exchanged among physiologically synchronized pairs, a serious disruption of sitting resulted. It is concluded that behavioral synchrony between the mates in the form of each pair's bond is as necessary as physiological synchrony in maintaining intermate cooperation in parental behavior of ring doves.