The Chestnut-sided Warbler (Setophaga pensylvanica) is a New World warbler. They breed in eastern North America and in southern Canada westwards to the Canadian Prairies. They also breed in the Great Lakes region and in the eastern USA.
These birds are migratory, wintering in Central America south to northern Colombia,with an unconfirmed sighting from as far south as Ecuador; they are also very rare vagrants to western Europe. They arrive in their breeding range in May and depart by mid-September.