Deceptive copulation calls attract female visitors to peacock leks.

Theory holds that dishonest signaling can be stable if it is rare. We report here that some peacocks perform specialized copulation calls (hoots) when females are not present and the peacocks are clearly not attempting to copulate. Because these solo hoots are almost always given out of view of females, they may be dishonest signals of male mating attempts. These dishonest calls are surprisingly common, making up about a third of all hoot calls in our study populations. Females are more likely to visit males after they give a solo hoot call, and we confirm using a playback experiment that females are attracted to the sound of the hoot. Our findings suggest that both sexes use the hoot call tactically: females to locate potential mates and males to attract female visitors. We suggest that the solo hoot may be a deceptive signal that is acquired and maintained through reward-based learning.