Purple Martins sing with boisterous, throaty chirps and creaky rattles. During courtship, males make a croak song that can be 4 seconds long; he only does this when a female is nearby, often before dawn and from inside the nest cavity. Females make a chortle song. The loudest song is the dawn song, which males sing before daylight, possibly to attract other martins to the colonial nest site.
The building blocks of their songs are also used as calls, in a variety of situations. In addition, martins make a hee-hee call while fighting over territories and zwrack and zweet calls during stressful interaction with other species. Females use a choo call for leading fledglings.
Males sometimes make click sounds during courtship by snapping their bills together.