Tree Swallows Are Migratory Songbirds

The system that I am studying is Tachycineta bicolor, commonly known as the tree swallow. Tree swallows are small, insectivorous, migratory songbirds. Young tree sparrows have mostly brown dorsal coloration, and adults have blue-green iridescent dorsal coloration in both males and females. Males develop their blue-green plumage much sooner than females, before their first winter (Lombardo, Bosman et al. 1995). Females retain their predominantly brown dorsal plumage typically until after their second year (Hussell 1983). Tree swallows are migratory birds, and are found throughout the United States and Canada during the spring and summer months, and migrate in late July and August to their overwintering grounds in the Southeast United States