The Eurasian duck is a species of duck found in Europe, Asia, and parts of North Africa. The scientific name for this species is Mergellus albellus, but they are commonly referred to as smews. Smews are small ducks that have a distinctive white patch on their wings and a black-and-white head. They are usually found near freshwater lakes and rivers, where they feed on aquatic insects, crustaceans, and mollusks. Smews are migratory birds, and they can often be seen in large flocks during the winter months.