Off the lek, males make a soft wut call when warning others of predators. Females give a variety of calls, though their function has not been well studied. When accompanying a brood, a soft, repetitive warning call indicates danger, while a single-note contact call helps keep chicks together. To distract or confront a predator, they use a loud hissing call. Females also call when soliciting males on the lek.
The outlandish male strutting display is a complex, finely timed sequence of sounds, both vocal and mechanical. It begins with two wing swishes, separated by about one second, that are achieved by the male heaving his vocal sacs, enclosed in a neck pouch, through his wings that are held rigidly at his side. The swish sound is produced when the rough feathers on the neck pouch are dragged through his wings, and is only heard when the bird is very close by. Following the wing swishes is a short series of low, clear cooing notes, then two booming pops from in quick succession from the large yellow air sacs. Between the two pops is a whistle, and a few seconds after the display’s conclusion, the head is quickly raised to emit a huffing or snorting sound — thought to be a final release of air.