The white-tailed nightjar (Hydropsalis cayennensis) is a species of nightjar in the family Caprimulgidae. It is found in the tropic regions of Central and South America. Taxonomy The white-tailed nightjar was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the other nightjars in the genus Caprimulgus and coined the binomial name Caprimulgus cayennensis. Gmelin based his description on "L'engoulevent varié de Cayenne" that was described in 1779 by the French polymath Georges-Louis Leclerc, Comte de Buffon in his Histoire Naturelle des Oiseaux. A hand-coloured illustration was also published. Based on a molecular phylogenetic study by Kin-Lan Han and collaborators published in 2010, the white-tailed nightjar is now placed with three other species in the genus Hydropsalis. This genus was introduced in 1832 by the German naturalist Johann Georg Wagler. The genus name combines the Ancient Greek hudro- meaning "water-" with psalis meaning "pair of scissors". The specific epithet cayennensis is from Cayenne, French Guiana, the type locality. Six subspecies are recognised: H. c. albicauda (Lawrence, 1875) – Costa Rica to north Colombia H. c. aperta (Peters, JL, 1940) – west Colombia and north Ecuador H. c. cayennensis (Gmelin, JF, 1789) – east Colombia through Venezuela and the Guianas to north Brazil H. c. insularis (Richmond, 1902) – northeast Colombia and north Venezuela and nearby islands H. c. leopetes (Jardine & Selby, 1830) – Trinidad and Tobago H. c. manati (Pinchon, 1963) – Martinique (Lesser Antilles) Description The white-tailed nightjar is long. Males weigh and females . Males of the nominate subspecies have grayish brown uppersides with brown to blackish brown speckles and streaks. Their face has a white or buffy supercilium and "moustache". The hindneck has a broad tawny buff collar. The wings are generally grayish to blackish brown with tawny and buffy markings. A white band shows on both the spread and folded wing. The tail appears slightly forked; all but the innermost pair of feathers are partially to completely white. The chin and throat are white. The breast is buff with a cinnamon tinge, brown bars, and bold white spots. The belly and flanks are white with a pale buff wash. The nominate females are darker overall. They do not have white on the wings or tail. The throat is buffy, the breast brownish, and the belly buff with