Intermediate forms of the species can also exist when their breeding ranges overlap like in the hybrid zone in the United States and western Canada.

[3] Black-fronted warbler, Setophaga auduboni nigrifrons is a subspecies found in Chihuahua to Durango, Mexico.

The juvenile male is similarly colored but with more black in its tail and can be distinguished by its incomplete wing panel.

[5] This form is distinguished from the myrtle warbler by its lack of a whitish eyestripe, its yellow throat, and concolorous cheek patch.

It is migratory, wintering from the southern parts of the breeding range into western Central America.

[2] Audubon's warbler tends to be rather active, typically spotted while catching insects during the warmer months in the year.

[2] During the colder months of the year Audubon's warbler is usually found eating berries and traveling in flocks.