The Common Eider is a large sea duck found in the northern regions of Europe, North America, and Asia. It is known for its distinctive plumage, with males displaying a striking black and white pattern, while females are mottled brown for camouflage. These ducks primarily inhabit coastal areas and are often seen diving for mollusks and other marine invertebrates. Common Eiders are social birds, often forming large flocks during the non-breeding season. They nest on the ground, typically in colonies, and the females use down feathers to line their nests, which provides insulation for the eggs. This down is highly valued and is often harvested for use in bedding and clothing.