Large scoter with distinctive white patch on wing. Males are black and have small white mark under eye, dark knob on the bill, and red-and-orange bill tip. Females are dark chocolate-brown and have two rounded white patches on face. Extremely similar to White-winged Scoter: note male’s much more angular head structure with steeper and more prominent protuberance and different bill coloration. Female is much more difficult to identify, but has more swollen-looking protuberance. Breeds in Russian tundra and taiga pools and lakes, winters on the coast; only very occasionally reported inland in the winter.