A fairly large, colorful swallow. Usually easy to identify with its long, forked tail and dark rump. Iridescent navy-blue above with a rich orange throat and forehead. Underparts vary across range, from bright buffy-orange to whitish. Occurs in any open habitat, especially large fields and wetlands. Often seen foraging in flocks, sometimes mixed with other species of swallow. Typically nests close to human habitation; builds a muddy cup nest in a barn or under a dock.