Rock-loving shorebird; breeds on Arctic tundra and winters on rocky coastline. Usually seen in flocks, sometimes mixed with turnstones or Surfbirds. In nonbreeding plumage, gray overall with white belly and dull greenish legs. Bill slightly droopy with dull greenish base. Breeding plumage variable across range; look for smudgy dark patch on belly and rufous on back. Similar to Purple Sandpiper but no range overlap.