Two days ago we had a flock of robins in the front yard along with a flock of totally black birds including their bill EXCEPT while they were on the ground you could see a white strip at the top of their folded wings. They were slightly smaller than the robins and a bit sleeker in looks.
The closest I can come from our bird book is a lark bunting ? BUT they evidently are not in our area. Wish I had a picture for you.
Terri