Although widespread across eastern South America, Least Nighthawk is mainly known from the savannas of southern Venezuela, Guyana, and northernmost Brazil, as well as, much further to the south, in the cerrados of south central Brazil. There are other, apparently much smaller, populations elsewhere in eastern Brazil, as well as over the lowlands of eastern Colombia. More data are needed to document whether Least Nighthawk is resident throughout this large geographic range, or whether, as is suspect, it undertakes local or even longer distance movements. Unsurprisingly, in light of this curious range, some five subspecies have been described, generally based on overall plumage coloration. As befits its name, this is a small nighthawk, distinguished from other species of Chordeiles by its usually obvious white trailing edge to the wings (buff in females), as well as its vocalizations, a short whit given in flight and a k-k-k-kurreee given in territorial defense. The diminuitive Least Nighthawk typically is found over natural grasslands, as well as other open country habitats, up to at least 1050 m, and it sometimes appears up to an hour or so prior to dusk. Least Nighthawk nests on the ground, laying a single cream or white egg.