Of all the ducks that reach the far north, the one that best symbolizes the Arctic is the King Eider. This hardy duck breeds on tundra along some of the northernmost shorelines in the world, including Arctic Russia, the northernmost Canadian islands, and the north coast of Greenland. Even in winter, it’s a northern species; North American populations spend the winter mostly in southern Alaska and along the coast of eastern Canada. However, small numbers come as far south as our middle Atlantic Coast and the Great Lakes in winter, and strays have appeared much farther south, so birders everywhere have reason to be aware of this species.
Many ducks show strong sexual dimorphism — that is, obvious visible differences between females and males: The females wear cryptic camouflage while the males show off with conspicuous bright colors. Eiders are extreme examples of this. The full adult male King Eider wears breeding plumage from late fall to early summer, and it’s an unbelievably gorgeous bird. However, females, young males, and adult males in the late summer “eclipse” plumage are subtler, requiring closer study.