It's been suggested that my yellow-faced warbler today might be
a female blackpoll--the drawing in Sibley shows the right color yellow on
the throat but not much on the face itself. How much variation
is there in these birds? The blackpoll looks closer than
black-throated green in Sibley (both of which look very different
in the Peterson I had with me today because it's so much lighter
and easier to lug around). The bird I saw today had a noticeably
yellow face.

--Pat

Pat Valdata, Elkton, MD | 
"The natural function of the wing is to soar upwards
and carry that which is heavy up to the place where dwells the race of gods.
More than any other thing that pertains to the body
it partakes of the nature of the divine." --Plato