The violet-green swallow nests in the western half of North America from Alaska to Mexico. Like the tree swallow, which are common in the eastern half of North America, they are cavity nesters. Since tree swallows are slightly larger they are more likely to take over prime nesting locations where the species range over laps in the middle of the continent. During the winter these swallows migrate to Central and northern South America. This is only the second time that we have seen this species in Yellowstone. Usually winter still has its grasp on the area when we visit so they do not return until after we leave. This year though, Yellowstone sent all of the cold and snow to Minnesota and they had a mild winter so the swallows had already returned. When we do see these birds it is usually around Old Faithful. They seem to like to nest in crevasses in the buildings.