In flight the Male Goosander in Winter looks black and white, it's clean white underside with no breast marks separates it from the Male Red-breasted Merganser.
The Male Goosander in winter has a dark green head, long red bill and white body which has a slight pink tinge. The back is black and it has a long tail.
Adult Male Winter
Notes: The Goosander is often seen in small family groups and tends to be a flighty bird, easily disturbed.
General distribution: Breeds in Iceland, Scandinavia and Northern Europe. Around 3500 resident pair breed in the UK, mainly in the North but some in the South. In Winter European birds move South with numbers in the UK drastically increasing to around 12,000 birds.
Habitat: The Goosander nests in upland areas near lakes and rivers close to woods. Outside of the breeding season it can be seen on freshwater lakes, rivers and reservoirs, occasionally it can be seen on estuaries and sea inlets.
The Male Goosander in Summer looks very similar to the Female and can be difficult to separate. The Male has a larger white wing patch than the Female. Note the Male and Female Goosander both have a sharply defined white throat with a clean line between brown and white, unlike the Red-breasted Merganser with which it is easily confused.
Thanks to: https://commons.wikimedia.org/wiki/User:Mdf;
Note the extent of the white on this Male Goosander combined with the dark back and head unlike the similar Red-breasted Merganser which has grey flanks and brownish-black breast. The white on the Goosander when seen up close often has a salmon pink tinge. Also note the long tail, most often held down to the surface of the water.
Adult Male Summer (Eclipse)
Long red bill, hooked tip
The Female Goosander has a blue-grey body, with a chestnut-red head and neck. The breast, chin and lower neck are white. The bill is long, red and hooked at the tip.
Note the contrasting dark head and light breast with the grey body and long hooked bill, making the Female Goosander a distinctive bird if seen clearly.