The family Caprimulgidae includes 9 species found in North America.

The caprimulgids occur in tropical and temperate regions and many oceanic islands. The soft plumage is cryptically colored with gray, black, buff and rufous in mottled and vermiculated patterns, often with white patches on the chin or throat. Most species range from 16-40 cm in length. A few species with long tails are up to 78 cm. The long wings are pointed and the birds are excellent flyers. Most species are active only at twilight or at night. During the day they perch quietly on the ground or lengthwise on a branch. The Common Poorwill of western North America hibernates in rock crevices during the winter. During hibernation the birds are torpid with a body temperature of 18-19°C, versus the normal temperature of 40-41°C.

The feet are small and weak. The bill is also small and weak. The gape is deeply cleft with large bristles around the side to help guide insects into the mouth. Most caprimulgids feed mainly or entirely on flying insects captured in continuous flight. No nest is constructed. The 1-3, usually 2, eggs are laid on the bare ground or on fallen leaves. The North American species of nighthawks sometimes nest on the flat, graveled roofs of buildings. The cryptically-colored eggs are white, gray or buff with markings of black, brown or violet. Both sexes incubate (about 16-21 days) and brood the young which are covered with gray or buff down. The hatchlings remain in the nest when born but soon become active, running about near the nest at night, but hiding under the female during the day. The active young deposit their excreta a short distance from the nest site in any direction, producing a ring of small white droppings around the nest. The adults collect insects in their crops during foraging flights and return to the young birds which take the parent's beak into their own. The parent then discharges the crop contents into the throat of the youngster.