The Common Nighthawk is a medium-sized bird, with dark brown plumage mottled with black, white and buff. It has long, slender, pointed wings and a long slightly notched tail. The head is large and flat, with large eyes, a small bill, and a wide mouth. In flight, a white patch can be seen on the wings of the adults.
Females can be distinguished from males by their throat band, which is pale yellow rather than white. The throat band on juveniles is mottled or absent. Adult males have a white tail band, which is lacking in most adult females.
Weight: 65 to 98 g (2 to 3.5 oz). Length: 21 to 25 cm (8 to 10 in).