Myrtle Warbler

The yellow rumped warbler has four subspecies, but there is a current proposal to split those subspecies into four separate species. Goldman's warbler, one of the subspecies, is found in the highlands of Guatemala and is non-migratory. The black-fronted warbler, another, is found in Mexico and is also non-migratory. Two of the subspecies are found in the U.S. and both are migratory and winter in the southern U.S. and down into Mexico, Central America and the Caribbean. The Audubon warbler is found on the western U.S. and the myrtle warbler is found in the eastern U.S. 

This flying bird gives the best look at various elements. You can just see the yellow patch on its rear, the yellow patch on the side and the white bars on the wings. It is in its brown, non-breeding plumage. 

Male Audubon and myrtle warblers both have yellow rumps and yellow side patches. The Audubon has a yellow throat and the myrtle has a white throat and a black mask. Females in breeding plumage have two white wing bars and adults in non-breeding plumage are brownish overall . They have thin, sharp bills and notched tails. 

You see the more whitish throat and a good dose of the yellow side patch. 

I saw this myrtle warbler in the Viera Wetlands near Melbourne, Florida. 

This photo shows the notched tail, but the yellow rump patch is covered by the wings.