Nightjar (ratchara) cryptically coloured birds of the family Caprimulgidae, order Strigiformes; to this order the owls also belong. The bird is characterized by its flat head, wide mouth fringed with bristles, large eyes, soft plumage and consequently noiseless flight. They tend to feed at dusk or at night by catching insects on the wing. There are 68 species of nightjars worldwide; Bangladesh has four species of which Grey Nightjar is endangered.
Savanna Nightjar (Caprimulgus affinis): length about 25 cm. Outer tail feathers all white except at tip in male, mottled in female. A buff coloured V from shoulders to half way down back when squatted. Spots in the middle of first four primaries white in male, rufous buff in female; Choto Ratchara (Indian Nightjar, Caprimulgus asiaticus): mottled grey-brown, buff and fulvous, black streaked above. White patches on wings conspicuous in flight; Dinkana/Ratchara (Grey Nightjar, Caprimulgus indicus): four outer pair of tail feathers with white spots in males; absent in females.
General plumage brownish buff with black streaks and spots as in other nightjars; Ratchara (Large-tailed Nightjar, Caprimulgus macrurus): resembles C. indicus. Blackish streaks on crown, a white spot on first four primaries and two outer tail-feathers broadly tipped white. [Md Anwarul Islam]