In their pioneering DNA-DNA hybridisation work, Sibley and Ahlquist found that the genetic difference between the eared nightjars and the typical nightjars was, in fact, greater than that between the typical nightjars and the nighthawks of the New World. Accordingly, they placed the eared nightjars in a separate family, the Eurostopodidae (9 known species), but the family has not yet been widely adopted. Subsequent work, both morphological and genetic, has provided support for the separation of the typical and the eared nightjars, and some authorities have adopted this Sibley-Ahlquist recommendation, and also the more far-reaching one to group all the owls (traditionally Strigiformes) together in the Caprimulgiformes. The listing below retains a more orthodox arrangement, but recognises the eared nightjars as a separate group. For more detail and an alternative classification scheme, see Caprimulgiformes and Sibley-Ahlquist taxonomy. †Ventivorus Mourer-Chauviré 1988 Subfamily Eurostopodinae Genus Eurostopodus (7 species) Genus Lyncornis (2 species) Subfamily Caprimulginae (typical nightjars) Genus Gactornis – collared nightjar Genus Nyctipolus – (2 species) Genus Nyctidromus – (2 species) Genus Hydropsalis – (4 species) Genus Siphonorhis – (2 species) Genus Nyctiphrynus – (4 species) Genus Phalaenoptilus – common poorwill Genus Antrostomus – (12 species) Genus Caprimulgus – (40 species, including the European nightjar) Genus Setopagis – (4 species) Genus Uropsalis – (2 species) Genus Macropsalis – long-trained nightjar Genus Eleothreptus – (2 species) Genus Systellura – (2 species) Subfamily Chordeilinae (nighthawks) Genus Chordeiles (6 species; includes Podager) Genus Nyctiprogne (2 species) Genus Lurocalis (2 species) Also see a list of nightjars, sortable by common and binomial names. Distribution and habitat Nightjars inhabit all continents other than Antarctica, as well as some island groups such as Madagascar, the Seychelles, New Caledonia and the islands of Caribbean. They are not known to live in extremely arid desert regions. Nightjars can occupy all elevations from sea level to , and a number of species are montane specialists. Nightjars occupy a wide range of habitats, from deserts to rainforests but are most common in open country with some vegetation. The nighthawks are confined to the New World, and the eared nightjars to Asia and Australia. A number of species undertake migrations, although the secretive nature of the family may account for the incomplete understanding of their migratory habits. Species that live in the far north, such as the European nightjar or the common nighthawk, migrate southward with the onset of winter. Geolocators placed on