Fairly large dark nightjar of woodland, edge, and adjacent clearings in northeast Mexico. Hunts mainly from perches at forest edge, sometimes even on fence posts in rather open areas. Cryptic plumage similar to other nightjars; both sexes have rusty collar on hindneck. Male has white tail corners. Female has narrower, pale buffy tail corners. Best detected and identified by voice: a slightly burry, 2-syllable "chi-wihw," repeated. Note similar Eastern Whip-poor-will, a winter migrant, in same areas.