The Nightjar family, Caprimulgidae is in the Order Caprimulgiformes.  They are crepuscular or nocturnal, catching flying insects.  The small beak hides a huge mouth as one may see as one yawns  in video below. Frogmouths are in a different family, Podargidae.

NIGHTJARS, FROGMOUTHS (Caprimulgiformes)

COMMON NIGHTHAWK (Chordeiles minor)

WHIP-POOR-WILL (Caprimulgus vociferus)

LESSER NIGHTHAWK (Chordeiles acutipennis)

Common Poorwill

Tawny Frogmouth

VIDEOS

Chicago, IL