High Quality Content by WIKIPEDIA articles! A nighthawk is a nocturnal bird of the subfamily Chordeilinae, within the nightjar family, Caprimulgidae. Nighhawks are medium-sized New World birds, with long wings, short legs, and very short bills. They usually nest on the ground and catch flying insects. The Least Nighthawk, at 16 centimetres (6.3 in) and 23 grams (0.81 oz), 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).