Laura Erickson's For the Birds

Perhaps the prettiest swallow of all, the stunning Violet-green Swallow of the American West averages slightly smaller than the Tree Swallow whose much wider breeding range encompasses much of the Violet-green’s. These two swallows live up to their genus name, Tachycineta, which means fast moving. The Violet-green Swallow’s specific epithet, thalassina, means of the sea, referring to the sea-green color of their backs.

Tree and Violet-green Swallows both nest in nest boxes and natural cavities. Most of the Violet-green Swallows I’ve been able to watch were nesting in crevices on buildings, something I’ve not seen many Tree Swallows do. Their nesting requirements put both species in competition with bluebirds. But one 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 bluebird chicks fledged, the swallows used the nest site for their own young.