The Short-tailed nighthawk (Lurocalis semitorquatus) is a species of nightjar in the family Caprimulgidae. These birds are sometimes called goatsuckers, due to the ancient folk tale that they sucked the milk from goats or bugeaters, their primary source of food being insects. The color of their plumage and their unusual perching habits help these birds remain unnoticed during the day.
The Short-tailed nighthawk is a rather large nightjar with an unusually short tail. Its upperparts are dark brown to blackish with rufous and buff spots and speckles. The wings are also dark brown with muted spots of several colors, and unlike most other nighthawks, do not have bold white markings. The tail is brown with tawny or grayish bars and a narrow buffy or whitish band at the end. The chin is dark brown, the throat white, the upper breast dark brown with lighter speckles, the lower breast buff with brown bars, and the belly and flanks tawny buff with brown bars. The subspecies differ somewhat in size and in the extent and intensity of the spots, speckles, and bars that overlay the ground color.
Short-tailed nighthawks are found in Mexico and across Central and northern South America. The northern populations are generally resident though the seasonal distribution of subspecies in Amazonia is not well known. The southern populations are migratory and may move as far north as Venezuela during the austral winter. These birds prefer to live in lowland evergreen forests but also can be found in more open landscapes such as clearings, river edges, old cacao plantations, and middle-aged secondary forests.
These birds are usually seen singly or in pairs. They may also sometimes forage in small flocks. Short-tailed nighthawks are aerial hunters and feed mostly at dusk. Their flight is "rapid and erratic" and has been compared to a bat's. They roost in trees, lengthwise on a thick branch. The most common vocalization of these birds varies slightly among subspecies; it has been described as a "constantly repeated but well-spaced ewIT ... ewIT ... ewIT ..." (L. s. nattereri) and "a sharp, slightly liquid g'wik or gweek" (L. s. stonei). Short-tailed nighthawks usually vocalize when perching in trees and in flight.
Short-tailed nighthawks are carnivores (insectivores). Their diet is known to include beetles and true bugs.
Unusually for members of their family, Short-tailed nighthawks nest in trees. Females lay a single egg on a large horizontal branch without using any added material.
Short-tailed nighthawks are not threatened at present but in some areas of their native range these birds suffer from deforestation.
According to IUCN Red List, the total population size of the Short-tailed nighthawk is 50,000-499,999 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.