The “after you” gesture in a bird

We observed that Japanese tits carrying a food item often fluttered their wings in front of their mates when perched nearby their nestbox with a food item. We proposed the hypothesis that wing-fluttering in Japanese tits functions as a gesture that prompts their mate to enter the nest first, and we tested this hypothesis in our study.

Analyzing the effects of social contexts and sex on the occurrence of wing-fluttering behavior, we found that parents flutter their wings only in the presence of their mate, with females performing this visual display more frequently than males. Next, we examined the effects of females' wing-fluttering and parental arrival order (which sex visited the nest first) on the nest entry order and the latency of males to enter the nestbox.