The Caprimulgiformes is an order of birds that includes the cosmopolitan nightjars, the frogmouths of Australasia and South-east Asia, the South American Potoos and Oilbird, and the Australasian owlet-nightjars. Nearly all are insectivorous and nocturnal.
The classification of the various birds that make up the order has long been controversial and difficult, particularly in the case of the nightjars. Traditionally, they were regarded, on morphological grounds, as being mid-way between the owls (Strigiformes) and the swifts. Like the owls, they are nocturnal hunters with a highly developed sense of sight, and like the swifts they are excellent flyers with small, weal legs. However at one time or another, they have lumped with owls, swifts, kingfishers, hoopoes, mousebirds, hornbills, rollers, bee-eaters, woodpeckers, trogons, and even hummingbirds!