Best time to see: mid Oct to mid Apr

Key facts

All dark sea-duck most often seen at sea as dark blobs bouncing on the water or flying low over the sea

Winter visitor to the UK from its breeding grounds in the Arctic and N. Europe

Recognition

Male all black except for orange mark on bill; female dark brown with pale cheeks; 47 cm

Gregarious, often forming large flocks up to 100 strong; feeds on cockles, mussels and other crustaceans by diving

Usually keep fairly close to shore; fly low over the water very fast, in line astern