the chimney swift ("chaetura pelagica") is a bird belonging to the swift family apodidae. a member of the genus "chaetura", it is closely related to both the vaux's swift and the chapman's swift; in the past, the three were sometimes considered to be conspecific. it has no subspecies. the chimney swift is a medium-sized, sooty gray bird with very long, slender wings and very short legs. like all swifts, it is incapable of perching, and can only cling vertically to surfaces.