It is the most conspicuous swallow at medium elevations. In the country the Patagonian subspecies can also be found, which is a migratory from the south of the continent. Its name Pygochelidon derives from the Greek roots puge = rabadilla y khelidon = swallow. The epithet cyanoleuca refers to its double coloration and derives from the Greek roots Kuanos = dark blue and leukos = white.Taken from : Wiki Aves de Colombia.
Other references: Wikipedia, Naturalista.