A large, heavy-billed loon. Common and widespread in North America; somewhat less common and more local in Europe. Breeding adults have gorgeous black-and-white patterning; especially note fully black head with iridescent sheen and boldly checkered back. Nonbreeding plumage is plainer gray above and white below; note the jagged border between gray and white on the neck. Heavy bill is usually held straight (compare with Yellow-billed Loon). Breeds on lakes and ponds in the boreal forest. Listen for their haunting, yodeling vocalizations. In winter, mostly found on nearshore ocean waters and sheltered bays, singly or in loose flocks.