A female White-breasted Nuthatch clings to the side of a tree in Blendon Woods Metro Park near Columbus, Ohio.
Nearly all female Nuthatches in this area have black crowns like the males rather than gray crowns like this one.
Gray crowns are more common on female Nuthatches in the Northeast. A second image of a Nuthatch is below.
Additional bird images are in my Birds and Animals gallery.