Barn Swallow

Overview

The barn swallow (Hirundo rustica) is the most widespread species of swallow in the world, occurring on all continents, with vagrants reported even in Antarctica. It is a distinctive passerine bird with blue upperparts and a long, deeply forked tail. In Anglophone Europe, it is just called the swallow; in northern Europe, it is the only member of family Hirundinidae called a "swallow" rather than a "martin".
There are eight subspecies of barn swallow, which breed across the Northern Hemisphere.

Summary from Wikipedia, available under CC BY-SA 4.0.