What is "common nighthawk"

Caprimulgidae \Caprimulgidae\ n. [L. capris goat + mulgere to milk.] a widely distributed natural family of nocturnally active birds including the whip-poor-will ( Caprimulgus vociferus), the chuck-will's-widow ( Caprimulgus carolinensis), and the common nighthawk ( Chordeiles minor); -- called popularly the goatsuckers or nightjars. The nighthawks are sometimes active during the day.

Syn: goatsuckers, nightjars, family Caprimulgidae.

The family . . . is alternately known as the nightjars (derived from the "churring" sounds of several species -- "jarring" the night air), or goatsuckers, a nonsense name that should be discontinued as it has its origin in the preposterous myth that the birds sucked the milk of nanny goats until they were dry.
--Terence Michael Short (Wild Birds of the Americas)

The common nighthawk (Chordeiles minor) is a medium-sized crepuscular or nocturnal bird within the nightjar family, whose presence and identity are best revealed by its vocalization. Typically dark (grey, black and brown), displaying cryptic colouration and intricate patterns, this bird is difficult to spot with the naked eye during the day. Once aerial, with its buoyant but erratic flight, this bird is most conspicuous. The most remarkable feature of this aerial insectivore is its small beak that belies the massiveness of its mouth. Some claim appearance similarities to owls. With its horizontal stance and short legs, the common nighthawk does not travel frequently on the ground, instead preferring to perch horizontally, parallel to branches, on posts, on the ground or on a roof. The males of this species may roost together but the bird is primarily solitary. The common nighthawk shows variability in territory size.

This caprimulguid has a large, flattened head with large eyes; facially it lacks rictal bristles. The common nighthawk has long slender wings that at rest extend beyond a notched tail. There is noticeable barring on the sides and abdomen, also white wing-patches.

The common nighthawk measures long, displays a wing span of weighs , and has a life span of 4 to 5 years.