Fig. 2

a Vocalization in relation to sex and type of a bird’s departure. Bars show the probability of a female (red) and male (blue) vocalization before the bird left the nest by flight (solid bar) or walking (hatched bar). Horizontal lines of black crosses denote estimates from a mixed-effect model with nest identity as a random intercept (Additional file 1: Table S2). The vertical lines denote 95% credible intervals of the estimates. b Sex-specific departure type before an exchange gap. Bars represent the relative proportions of exchange gaps (i.e. parents exchanged during the incubation recess) after female (red) and male (blue) incubation bouts with distinction between walk (hatched bars) and flight (solid bars) departures. In addition, dark colours indicate vocalization of a departing bird