The 'after you' gesture in a bird.

Gestures are ubiquitous in human communication, involving movements of body parts produced for a variety of purposes, such as pointing out objects (deictic gestures) or conveying messages (symbolic gestures). While displays of body parts have been described in many animals, their functional similarity to human gestures has primarily been explored in great apes, with little research attention given to other animal groups. To date, only a few studies have provided evidence for deictic gestures in birds and fish, but it is unclear whether non-primate animals can employ symbolic gestures, such as waving to mean 'goodbye', which are, in humans, more cognitively demanding than deictic gestures. Here, we report that the Japanese tit (Parus minor), a socially monogamous bird, uses wing-fluttering to prompt their mated partner to enter the nest first, and that wing-fluttering functions as a symbolic gesture conveying a specific message ('after you'). Our findings encourage further research on animal gestures, which may help in understanding the evolution of complex communication, including language.