What type of bird is a goldeneye?

The common goldeneye is a medium-sized sea duck of the genus "Bucephala", the goldeneyes. Common goldeneyes are aggressive and territorial ducks, and have elaborate courtship displays. They are found in the lakes and rivers of boreal forests across Canada and the northern United States, Scandinavia, the Baltic States, and northern Russia. They are migratory and most winter in protected coastal waters or open inland waters at more temperate latitudes. Naturally, they nest in cavities in large trees, where they return year after year, though they will readily use nest boxes as well.

Common goldeneyes are diving birds that forage underwater. Insects are the predominant prey while nesting and crustaceans are the predominant prey during migration and winter.