In the summer, this bird is much more dramatic looking, with sharply contrasting red and black across the wings and a large black belly spot. In winter, it's much more subdued, as shown in the picture here. This medium-sized shorebird (6-9" long) can be spotted by its very round appearance, combined with a long, downturned, beak.
Last weekend marked one of my best opportunities to photograph a group of Dunlin. They were sleeping and feeding about 20 feet away, and the picture shown was the result.