白嘴潛鳥 Gavia adamsii

A large, heavy-billed loon of the High Arctic. Much like a Common Loon but with a thicker neck and blockier head. Pay special attention to the bill: note straight upper edge, angled lower edge, and all-pale yellowish color (especially the tip). Breeding adults have gorgeous black-and-white patterning; especially note boldly checkered back and thick lines forming a necklace. Nonbreeding adults and juveniles can be quite pale and sandy brown, especially on the face and neck. Beware the bill of Common Loon can appear very pale in some lighting, but always has a dark line along the top all the way to the tip. Breeds on ponds in the tundra. In winter, mostly found on nearshore ocean waters and bays.