or whistler Either of two species of small, yellow-eyed diving ducks that produce a whistling sound with their rapidly beating wings. The common goldeneye (Bucephala clangula) breeds throughout the Northern Hemisphere; Barrow's goldeneye (B. islandica) breeds primarily in northwestern North America and Iceland. Both winter mainly in northern coastal waters. Both are about 18 in. (46 cm) long and have a black back marked with white, white sides and breast, and conspicuous white patches in front of the eyes. The head of the common is dark green; that of the Barrow's is purplish black. Both nest in tree cavities and prefer a diet of aquatic invertebrates. They are prized as game birds