The Dusky Crag Martin is a small swallow with a dark brown back and paler underside. It catches insects in flight around cliffs and buildings.
It is about 13 cm long, with sooty-brown upperparts and paler underparts. Its short, square tail has small white spots, and the sexes look alike.
It catches midges and other small flying insects around cliffs and buildings. At the Kaiga site in India, it was recorded building mud nests on buildings during the monsoon.
An extinction-risk assessment has not been added yet.