The nominotypical subspecies Oxyra jamaicensis is native to eastern North America. Its wintering areas are in the southern parts of the United States and the northern parts of South America. The other two subspecies of ruddy duck are present in South America. During the nesting season, ruddy ducks prefer lush inland lakes and wetlands. Its wintering areas are often situated in shallow bays. The primary nutrition of ruddy ducks is aquatic plants and insects.

The first ruddy ducks were introduced to Europe, the United Kingdom, in the 1940s. From wildfowl collections, ruddy ducks spread first to Ireland and then to Belgium and soon became established in other parts of continental Europe. In the British Isles, the population peaked in the 2000s, with an estimated 7,000 specimens.

There have been 40 reported sightings of the ruddy duck in Finland in the last twenty years, totalling 56 specimens. The most recent sighting was in Pietarsaari in June 2011. Most observations are made in the spring and summer, in the lush bays along the sea coast and on lakes.

Ruddy Duck – Oxyura jamaicensis