In spring, warblers are in their most colorful plumage. This is a male Chestnut-sided Warbler; the female looks similar but a little less colorful. This species goes through a molt during the summer. By fall, the black on the face will be gone, replaced by gray. The back and the top of the head will be greenish yellow and they will have a white eye ring. The male will still have the chestnut sides but the female may not have any. This makes them a good example of what birders call “confusing fall warblers”. Chestnut-sided Warblers breed in southeastern Canada and the northeastern United States from Minnesota to Maine. Their breeding range also extends into the Appalachian Mountains. In winter they are found in Central America.
From May 22, 2011 - Migrating Warblers