Alexander's Swift or Cape Verde Swift (Apus alexandri) is a small bird of the swift family found only in the Cape Verde Islands. It has been recorded from all the islands except Santa Luzia although it probably breeds only on Santiago, Fogo, Brava, Santo Antão and São Nicolau. It is generally common with a stable population and is not considered to be threatened. It can be seen flying over all habitats and hunts in flight for insects, foraging in flocks over gullies and along cliffs and shorelines.
It is 13 cm long with a wingspan of 34 to 35 cm. The plumage is dark grey-brown with a large pale throat-patch. Compared to other swifts recorded from the islands it is smaller with shorter wings and a shallower fork to the tail. Its flight action is weaker and more fluttering. It has a high-pitched, screaming call with a buzzing quality.
The nest is built in a crevice in a cliff, in a cave or in the roof of a building. It is saucer-shaped and made of grass and feathers. The eggs are white and a clutch size of two has been reported.
The name of the species commemorates Boyd Alexander, an English ornithologist who led two expeditions to the islands in 1897.