Large-bodied diving waterbird, breeds on floating mats of vegetation on lakes and ponds in the boreal forest. In winter, mostly found on bays and open ocean, singly or in loose flocks. Breeding adults have gorgeous black-and-white patterning. During the winter, plain gray above and white below. Note heavy bill held straight. Dives to catch fish in deep, clear water. Their haunting, yodeling vocalizations are classic sounds of northern lakes and ponds.