Shore Birds

Seeing these tiny birds playing tag with the tide always makes us laugh. They move so fast on those little legs that it's almost impossible to see anything but a blur as the whole flock skims across the sand and pecks and runs some more. Unfortunately there is nothing in this frame to show scale--they almost look like gulls. But they are about the size of your fist, nervous little things pecking in the sand. I got lucky here--they were standing still for a couple seconds. Anybody know what they are?