Sri Lanka frogmouth – batrachostomus moniliger
is a small frogmouth found in the Western Ghats of south India and Sri Lanka. Related to the nightjars, it is nocturnal and is found in forest habitats. The plumage coloration resembles that of dried leaves and the bird roosts quietly on branches, making it difficult to see. Each has a favourite roost that it uses regularly unless disturbed. It has a distinctive call that is usually heard at dawn and dusk. The sexes differ slightly in plumage. This bird reaches 23 centimetres (9.1 in) in length. Like all frogmouths, this species has a wide and hooked bill with slit-like nostrils and the large head with eyes facing forward to provide a wide field of binocular vision. Compared to others of its genus it has small wings, which are distinguished by the wing coverts ending in black spots tipped with white. The male is gray-brown with fine barring and a spotted crown. Some males are browner and look more similar to females. The female is more rufous or chestnut brown. Indian female birds have very fine black speckles on the crown but Sri Lankan females may lack or may have reduced markings.

It sounds like this
Recording by Peter Boesman from Xeno canto