In alternate plumage, the bright orange throat and face pattern of the male are diagnostic. Often, the face pattern cannot be seen as the bird forages high in the canopy. However, the orange breast and black streaks on the sides are distinctive. Female and immature plumages are duller but can be distinguished by the broad yellow supercilium contrasting with the brownish crown and cheek. In fall, Black-throated Green Warbler is similar but has a greenish cheek and crown that don't contrast much with the yellow supercilium. Townsend's Warbler also has a broad yellow supercilium but has a darker cheek and crown making the face pattern appear much more striking. Both Townsend's and Black-throated Green Warblers lack the pale streaks on the back of the Blackburnian.