The distinctive Harlequin duck is a beautiful small sea duck with a small bill, short neck, and long tail. Males in breeding plumage are unmistakable with their dark blue color, reddish brown sides and crown, and striking white patterning on the face, neck, sides, and back. Unlike most waterfowl that prefer quiet marshes, the Harlequin duck breeds on fast-flowing streams and winters along rocky coastlines in the crashing surf.
Harlequin ducks are well adapted to their harsh surroundings. They make their way against the current and easily climb up steep and slippery rocks, although many have been found with broken bones presumably from being dashed against rocks in the rough surf. Like other diving ducks, they forage underwater for crustaceans and mollusks, insects, and small fish found in riverine and marine habitats.
The Harlequin duck is sometimes called a sea mouse for its very unducklike squeaks. You can listen to the Harlequin duck here.