Scientific name: Bucephala islandica (J. F. Gmelin, 1789)
Bird group: Ducks
Field characters. 42-53 cm. Similar to Common Goldeneye, but somewhat larger and heavier, and male with crescentic white patch between eye and bill, and flat-crowned, bulbous, oval head. Male with more black on sides of body, and with black head glossed purple and violet; large white patches on black scapulars. Female resembles female Common Goldeneye but is slightly larger with shorter and deeper bill (however overlap occurs), steeper forehead, and darker chocolate-brown head with mane at the back.
Voice. Generally silent; during courtship male produces grunting and clicking calls.
Distribution. Locally fairly common breeding bird on Iceland.
Habitat. In the breeding season restricted to productive lakes and pools with floating or emergent vegetation; also on rapids and streams. Nests in tree-holes. Moves outside breeding season to nearest ice-free waters.
Food. Food (chiefly insects and larvae, molluscs, crustaceans) obtained mainly by surface-diving up to depth of 3.5 m.
Eggs. Initially without markings, sometimes becoming blotched with pale brown markings during incubation. Ground colour bluish-green. Texture smooth, not glossy. Shape subelliptical/short subelliptical. Size 62 x 45 mm (57-65 x 42-48), weight 64 g (58-66). Closely similar to Goldeneye, but more bluish .