You may look at this and think this is clearly a Yellow-rumped Warbler, Myrtle subspecies. It has all the characteristics. However, notice the slight yellow tinge to the throat. A young male has a more buff colored throat, according to Sibley's Guide. Therefore, I think this yellow throat belies some Audubon ancestry way back in the archives. Purely a guess, but the Myrtle should be all white.