These swallows are seen all year in central to coastal California. During the summer or nesting season, they are seen throughout the west coast from southern California to Alaska and inland to and including the Rocky mountains. Their winter range is south of the US border in much of Mexico and some area of central America.

Frequent along the coasts and in the mountains where they nest as small colonies in tree hollows, bird houses or rock crevices.

Much like the tree swallow but the underbody white extends onto the rump and over the eye. Black in front of the eye and above beak. The bright green back and top of head contrasts with the purple rump. Wing primaries are brown with gray.

Females are duller. Juveniles are gray-brown above with a dusky wash across the breast.

After stopping at the Kootenai Falls, I continue my drive on the northern tier highway following US 2 to Libby, Montana, then left on SR 37 and take this highway north along the Kootenay river to the Libby Dam. While photographing the dam, I see a green bird preening himself on a post.

In the few minutes he is siting on the post, I take as many photos as my camera allows me to, then he turns to look at me and he is gone.