Goatsucker, or Nightjar, a migratory, night-flying bird of Europe and North America. The names come from the mistaken belief that these birds suck goats' milk, and from the harsh, jarring sound made by the male. An adult goatsucker is about 10 inches (25 cm) long and has mottled, brownish plumage. It has large eyes and a large mouth; a small, hooked beak; and a broad tail. The bird perches on the ground by day, rising at dusk to catch flying insects. American species include the whippoorwill; chuck-will's-widow, and nighthawk.
Goatsuckers belong to the family Caprimulgidae.