The male is 66 cm (26 in) long including the tail streamers and weighs about 42 g (1.5 oz).

In Colombia it is found in the Central and Eastern Andes, on the main Andes' west slope in northern Ecuador and northwestern Peru, and on the east slope for the entire length of Ecuador, most of Peru, and well into Bolivia.

[6] The swallow-tailed nightjar's breeding season has not been defined though it appears to include August and September.

The one nest that has been described in detail was a depression in the ground lined with dried leaves and dead twigs and cntained one egg.

The swallow-tailed nightjar's song has been described as "unmistakable and beautiful ... a vibrating worr-r-r-e-e-e-e-e-r, at first sliding up, then dropping down", and is sung from the ground.

It also makes "a liquid, rising pwip, and a musical mellow stuttered whistle when agitated".