Sanderling: Calidris alba
You'll know a sanderling even from a long distance by the way they scramble away from the wash of waves upon the beach, just barely keeping astride of the frothing water –– only to dart back amongst the exposed molluscs when the water slides back. Back and forth, like a beached extension of the waves. A sanderling is a little larger than a robin, and has brown-black plumage with a white belly; their medium-sized bill and legs are black. They are a cosmopolitan species and can be seen on nearly every beach in the world.