Lomax, your's looks like a yellow-rumped warbler to me. They have been visiting my feeders all winter.
Now, here's one I just can't ID. I feel that I've seen it before but just can't remember what it is. I keep thinking it's a female brown-headed cowbird, but it's too small and the markings are too subtle. This one is sparrow sized; shot about a week ago in deep south Alabama. Anyone?
STVest, I think you are right on the mark, that looks like an adult female cowbird. Check it out here: