Subspecies A. a. parvulus is smaller than the nominate and the borders between black and white areas are very sharply defined.

Its tail is shorter and less deeply forked, its white plumage is purer, and it has darker undertail coverts.

[5] Subspecies A. a. parvulus of the Andean swift is the northernmost; it is found on the western slope of the Andes from Peru's Cajamarca Department south into far northern Chile's Tarapacá Region.

[5] The Andean swift mostly inhabits semi-arid montane scrub landscapes though it is also found in both drier and more humid areas.

[5] The Andean swift is a year-round resident throughout its range, though it may temporarily move to lower elevations to avoid snowstorms.

[1] It is generally considered common, though uncommon in northern Chile and "local and irregular" in parts of Argentina.