The Puerto Rican nightjar or Puerto Rican whip-poor-will (Antrostomus noctitherus) is a bird in the nightjar family found in the coastal dry scrub forests in localized areas of southwestern Puerto Rico. It was described in 1916 from bones found in a cave in north central Puerto Rico and a single skin specimen from 1888, and was considered extinct until observed in the wild in 1961. The current population is estimated as 1,400-2,000 mature birds. The species is currently classified as Endangered due to pressures from habitat loss. Description Puerto Rican nightjars, whose song is composed of rapid "whip" notes, are small birds about 22–23 cm in length, weighing 39-41 g. Similar to the Antillean nighthawk, the species has a mottled, black, brown and gray colored plumage which serves as camouflage while the bird is perched on the ground. Males have a black throat with a white thin horizontal line. There are white spots on the lower part of the tail which are visible in flight. Females are of a buff rather than white coloration. Puerto Rican nightjars have large, dark black eyes, a short gray bill, and gray tarsi. Like all nightjars, they possess stiff bristles around the beak to help with the capture of insects in flight. History The Puerto Rican nightjar was first discovered as a single skin specimen found in the Northern part of Puerto Rico in 1888, and rediscovered and correctly identified in 1916 when bones were discovered in a cave in northern Puerto Rico. The species was originally considered already extinct at the time of its discovery. Confirmation of living specimens only occurred in 1961 in the Guánica Dry Forest. Detailed studies of the species started in 1969. Distribution and habitat The species is likely to have historically occurred in moist limestone and coastal forests in northern Puerto Rico, in addition to the current range of dry limestone, lower cordillera and dry coastal forest. The nightjar is presently mostly found in closed canopy dry forest on limestone soils with abundant leaf litter and an open understorey. Lower densities are present in open scrubby forests. Populations have so far been confirmed in three locations in the southwest of the island: Susúa State Forest, Guánica Dry Forest and Guayanilla Hills. The first nesting record of the Puerto Rican nightjar in Maricao State Forest was reported in 2005. Ecology The Puerto Rican nightjar feeds on beetles, moths and