Scientific name: Mergus merganser Linnaeus, 1758
Bird group: Ducks
Field characters. 58-66 cm. With lengthy and slender body; larger than Mallard, with thin blood-red bill and red legs. Male has white breast and sides tinged with salmon-pink, black back, green-black head; grey rump and tail. In flight male easily distinguished by white body and wings, black head, and primaries; wing black on outer half and white on inner half. Female with chestnut head with obvious, even crest, throat with distinct white patch, blue-grey upperparts, grey flanks. Wing pattern in flight shows black primaries, blue-grey forewing, large white speculum crossed by incomplete black line. Juvenile as female but with shorter crest, less intense head colour, chest and upperparts duller grey.
Voice. Generally silent; during display male utters various soft calls; female has harsh, guttural call.
Distribution. Fairly common breeding bird in Fenno-Scandia, more rare in other parts of Europe.
Habitat. In breeding season, prefers large clear lakes in forested, mountainous regions; nests in tree-holes, rock crevices, holes in walls, or in artificial structures such as nest-boxes; in winter, mainly on freshwater of lakes and rivers.
Food. Catches mainly fish after foraging with head submerged and subsequent diving. Prey may be swallowed under water or be brought to surface. Prefers to fish in shallow waters up to 4 m.
Eggs. Unmarked, ground colour cream/creamy-white. Texture smooth. Shape subelliptical/short subelliptical. Size 68 x 47 mm (62-74 x 42-49), weight 84 g (69-98).