The Red-breasted Merganser (Mergus serrator) and the Mallard (Anas platyrhynchos) belong to the same orders of ducks, anseriformes, and the same family, anatidae. The Merganser is a fish-eating duck, a great diver, and mostly stays in freshwater lakes. It is a migratory bird in Iceland. The Mallard is a dabbling duck, it doesn’t dive but tips forward in the water to find food. It stays in Iceland the whole year but goes down to the shore in the winter time. Both of these ducks are common in Iceland.
The Mallard (Anas platyrhynchos) is the biggest of the dabbling ducks. It is the most common and widely spread duck in lowlands in Iceland but it is scarce in the interior. Most of them overwinter in Iceland, staying by the seaside or in the sea. Some probably go to the British Isles for winter. The breeding population in Iceland is estimated around 15,000 pairs.