Harlequin ducks are compact birds; their 1-1/2 pound bodies measure 15-21 inches. They have a wingspan of 24-28 inches.

Harlequin ducks are also known as "painted" ducks; they are named after Harlequin clowns. This name may have derived from the colorful markings of the male harlequins; the bluish-gray body is dashed with white and chestnut patches and stripes. Females have brown bodies and three white spots on their head; their coloration helps to camouflage them while they care for the eggs and young.

These birds live in and near rough, swift waters. In the winter, they can be found in rocky, sometimes turbulent, coastal waters. During other times of the year, they may be seen in rushing pristine mountain streams.

Harlequin ducks feed by day. Their remarkable ability to swim allows them to dive beneath the surface of quick moving water. The ducks use their feet and wings to walk under water along the rocky bottom to feed on, algae, aquatic insects, mollusks, and small fish.

To protect themselves from predators at night, harlequins roost on rocks in the middle of quick flowing streams, creeks, and rivers. The female harlequins select a nesting site along a rushing mountain stream. While the males defend the nesting area, females build the grass and feather-lined nest in a tree hole, on a rocky crevice, or under a bush.

Once the eggs are laid, the males desert the females and return to the sea. The females will incubate the five to six eggs and lead the young to a secluded part of the river. Often several broods will come together and may be joined by females who were unsuccessful with nesting that year. Once the clutches have fledged, the females and young depart the streams for the sea, where they will spend the winter.

When harlequins fly, they keep low and move quickly just above the surface of the water. Perhaps this flight strategy helps to avoid being seen, and subsequently eaten, by predators.

"...(T)here is concern that the population of harlequins...may be affected by the cumulative impacts resulting from habitat loss in the upper Skagit and potential future impacts resulting from management decisions and policy regarding resource use" (Christophersen & Kuntz, 1997).