Olive green above, yellow below.
Males have distinctive black cap.
Breeding range from Alaska south to southern California and western mountain regions to Colorado and northern New Mexico, west across Canadian provinces to Newfoundland south to northern New England and Minnesota. Breeds in moist habitats with dense ground cover. Winters primarily from northern Mexico to Central America and the Caribbean. Small numbers winter along Pacific Coast and along the coastline of Gulf states. In the East, migration is circum-Gulf.