Awesome photo - as woodsac said extremely clear and defined. I was just wondering how far away you were when you took this shot and what lens you were using?
While the female looks something like this, Goldfinch colors
mute in wintertime. This one is still changing. In summer
the males have a black mark atop their head. It runs from
their bill over their eye to about the center of their head.
You can still see some of that color on this bird. Also the
white color of their underside is a sign of winter coloring.