Jerdon's nightjar (Caprimulgus atripennis) is a medium-sized nightjar species native to southern India and Sri Lanka. Formerly considered as a subspecies of the long-tailed nightjar, it is best recognized by its distinctive call which sounds like a wooden plank being beaten periodically with each note ending in a quaver. The common name commemorates Thomas C. Jerdon who described the species.
Taxonomy
thumb|C. a. aequabilis<br />[[Sri Lanka|left]]
Thomas C. Jerdon first described this species in an annotation to his 1845 treatment of the jungle nightjar (C. indicus) in the Illustrations of Indian ornithology. Subsequently, it was sometimes lumped again with C. macrurus, but the co-occurrence of this form and large-tailed nightjar C. macrurus without interbreeding in the northeast of the Indian peninsula was noted in 1987 suggesting their distinctness. It has since been reaffirmed as a full species based on studies of their vocalizations. The subspecies in Sri Lanka is C. a. aequabilis. Jerdon's type locality mentioned as Ghauts has been considered to be the Eastern Ghats west of Nellore.
Description
Like other nightjars, it has a wide gape, long wings, soft downy plumage and nocturnal habits. At 26 cm in overall length, it is almost a head's length larger than the Indian nightjar (C. asiaticus), and differs from that species in its barred tail, rufous rear neck, and wing bars. The vermiculations on the crown are fine giving it a nearly uniform shade. The collar is blackish. The male has a white patch on each wing. Otherwise, their cryptic plumage is mainly variegated buff and brown, as typical for the dark tropical woodland nightjars.
Its typical call is a fast repetitive ch-woo-woo.