The song of Scissor-tailed Nightjar is described as "a prolonged sequence of tsips ....., one note per second just like a cricket, sometimes for minutes on end" (Sick 1993) and as "a thin, peeping ti" (Lane, in Schulenberg et al. 2010).
For a representative audio recording with sonogram, see audio
This song sometimes is accompanied by "a low raspy rhi rhi-grrr", which may be a separate vocalization or perhaps is a mechanical sound (Lane, in Schulenberg et al. 2010). The song is given both when perched ("perched crosswise on a small branch or other substrate") or in flight, at dusk and dawn (Sick 1993).
Calls of Scissor-tailed Nightjar include a flight call, described as "an extremely high tsig (in flight), sounding like [the] voice of a cricket or bat" (Sick 1993), a low clucking sound, and a low growl that occasionally terminates in a croak (given by a wounded bird, possibly as an attempt to startle a predator; Wetmore 1926).