Small shorebird, falls into group called "peeps." Most similar to Least and Western Sandpiper. Shorter, blunter bill than Western without rufous tones in summer. Paler and grayer-brown than Least. Often in large flocks on mudflats, sometimes beaches. Winters in South America; very rarely lingers in the U.S., unlike Western Sandpiper. Breeds on arctic tundra. Seen in the continental U.S. only during migration.