Medium- to long-distance migrant. Some migrants winter in the southern U.S.; others go all the way to South America. They migrate primarily during the day, and with other species of swallows, particularly Cliff, Tree, and Barn Swallows. They generally arrive on breeding grounds in North America in early spring, between mid-March and late May. Hundreds to thousands can be seen migrating south in mixed swallow flocks from July through October.