Small gray swift with a pale gray rump and belly that are marked with black streaks. With a very good view, tiny spines on the tail can be seen. Seen in flight over all habitats on the islands of Sao Tome and Principe. The call is a high-pitched “sip.” Similar in size and shape to Little Swift, but separated by the pale belly and grayish rather than bright white rump. Also similar in size to African Palm Swift, but has a much shorter square tail and a pale belly and rump.