The buff-collared nightjar or Ridgway's whip-poor-will (Antrostomus ridgwayi) is a species of nightjar in the family Caprimulgidae. It is found in Guatemala, Honduras, Mexico, Nicaragua, and the U.S. states of Arizona and New Mexico.
The buff-collared nightjar is 22 to 23 cm (8.7 to 9.1 in) long. The head, upperparts,and tail are brownish gray with gray, cream, and rust markings. It has a bright cinnamon buff collar on the hindneck and a narrow buffy white band under the throat. The wings are brownish black with cinnamon buff bands. The breast is brownish gray and the belly tan with dark brown bars. The ends of the two outermost tail feathers have much white in the male and a small amount of buff in the female.