Violet-green Swallows are velvet green on their upperparts with white underparts and a forked tail; they have white patches on the side of the rump. The head is usually more coppery or brownish than the back, and the rump is a glossy violet color. They nest in cavities in a tree or rock crevice, sometimes forming small colonies.
Fun Fact A pair of Violet-green Swallows was observed assisting a pair of Western Bluebirds in raising young. The swallows guarded the nest and tended the bluebird nestlings, and after the bluebirds fledged, the swallows used the nest site for their own young.