including Archbold's nightjar (Eurostopodus archboldi) and the Papuan nightjar (Eurostopodus papuensis), which it most resembles in appearance and habitat preference. Though Satanic nightjars have always been treated as a single species, recent comparisons of photographed and observed individuals have revealed differences which could indicate there are in fact two separate types. Individuals from central Sulawesi have grey on their tails and scapulars, along with white-tipped, oval-shaped breast feathers. Conversely, individuals from the north of the island lack grey markings and have less pronounced breast feathers. Regional differences in the birds' song may also exist. However, more evidence must be gathered before any conclusions can be drawn. Distribution and habitat The Satanic nightjar is restricted to Sulawesi, Indonesia. It inhabits lowland and mountain rainforests of the region from 250 to 2300 meters above sea level. It seems to favour edge habitats with low canopies and groves of palms and rattans. It can be found in forest clearings, as well as open spaces created by roads and trails in old-growth forests. While it has mostly been sighted in the north and central parts of the island, its range could extend over all of Sulawesi. Behavior Vocalizations The Satanic nightjar makes a range of different vocalizations. While flying, the bird produces a burst of loud, ascending, "fWIP! fWIP" notes set at 1 second intervals. These notes can also occur more sporadically, sometimes sung suddenly and close-together in pairs of "fWIP-WIK!, fWIP-WIK!" where the last note is shorter and sharper than the first. When at rest, the bird might trill a string of quick, constant notes "TWIk-TWIk- TWIk" which sound similar to its paired calls. Each note begins loudly but ends softly and the song generally decreases in volume and pitch, lasting about 2–6 seconds. In one recorded trill call, the song was preceded by a small number of weak, low qu/wick! sounds. When disturbed, the nightjar may also make growling noises, which accompany a threat display. Nonetheless, the bird vocalizes rarely, which may partly explain its elusiveness. Diet Like other nightjars, this bird preys on insects while flying. It hunts along the forest edge, active near dusk and dawn. However, little is known about its diet. It is thought to feed primarily on nocturnal insects such as moths. Reproduction The Satanic nightjar has a generation time of 5.4 years. It breeds from March to October, though this range might actually encompass two distinct