Dear fellow Ospreyers. I fear I fell into the orange-crowned warbler 
trap when I announced that I'd spotted a Nashville at Hunting Creek. 
Subsequent research leads me to believe that the variability of 
orange-crowned warblers led this gray-headed, yellow-bodied, faint 
eye-ringed bird to lead me. It seduced me into believing it was 
something  more rare. Anyway, I'm pleased to have seen (most 
probably) an orange-crowned.

I felt confident at the time, but the more reading and photo-skimming 
I do on orange-crowneds, the more I think I may have made an error. 
Five things point me in that direction:

1) the eye ring was not as even and distinct as I would have liked
2) the chin was whitish, as was a bit of the throat
3) the grayish on the head and far upper back could be consistent 
with some orange-crowned warbler plumages (I'd forgotten this earlier.)
4) the whitish break between vent and the rest of the rich yellowy 
underparts was not as wide as I've seen in Nashvilles. In fact, it 
was very narrow, more an edging.
5) Call: thin, not sharp as in Nashville, but only heard once.
In addition, the bird wasn't as active as I'm used to seeing in 
Nashvilles and the yellow tone was richer, perhaps more toward 
olive-yellow tones of many orange-crowneds, not the flat yellow of Nashvilles.

However, there was no discernable dull streaking on the underparts. 
Did not see any trace of blackish in the eyeline. Tail action: none 
if any while foraging.

I leave you with this from Kenn Kaufman's Advanced Birding Peterson guide:

"A good rule of thumb, when you suspect that you've found any of 
these rare and relatively unpatterned warblers in winter, is to ask 
yourself: Why isn't this bird an orange-crowned warbler?"

Howard Youth
Bethesda, MD