A nighthawk is a nocturnal bird of the subfamily Chordeilinae, within the nightjar family, Caprimulgidae. Nighthawks are medium-size with long wings, short legs, and very short bills. They usually nest on the ground. They feed on flying insects. The least nighthawk, at and , is the smallest of all Caprimulgiformes. Nightjars are sometimes referred to as goatsuckers from the mistaken belief that they suck milk from goats (the Latin for goatsucker is Caprimulgus).