155391 Red-breasted Merganser Mergus serrator L 52-58cm. Slim duck with shaggy, spiky, crest. Dives frequently in search of fish. In flight, all birds show white on upper surface of inner wing; extent is greatest in male. Sexes are dissimilar in other regards. Adult male has narrow red bill, green head, white neck and orange-red breast. Flanks are grey and back is black. In eclipse, similar to adult female but retains extensive white on wing. Adult female has red bill, dirty orange head and nape and paler throat; body is otherwise greyish buff. Juvenile resembles adult female. Voice Mostly silent. Status Nests beside fish-rich lakes and rivers, mainly in N; locally common. Influx from N Europe boosts numbers in winter and then common on estuaries and sheltered coasts.