Long-distance migrant. Tree Swallows begin migrating south in July and August, flying during the day and roosting in large flocks at night. Eastern populations probably migrate along the Atlantic coast to winter in Florida and Central America. Except for the individuals that winter in Cuba, most Tree Swallows probably migrate along the coast to their wintering grounds rather than going over the Gulf. Populations from the Midwest and the Canadian prairies may follow the Mississippi River southward; Western populations probably travel along the eastern Rockies and along the Pacific coast.