The following link has photographs of an apparent female MacGillivray's Warbler
that Arun Bose and myself observed in Hopewell, Virginia this morning.
I apologize for the quality but cummulatively I think they demonstrate all of
the pertinent fields marks to discern the bird from other similarly plumaged
species.
http://www.visitingnature.com/macgillivrayswarbler.htm
Best of success for those who might pursue this bird.
Enjoy each day,
Allen Bryan
Richmond, Va.
www.visitingnature.com