A medium-sized loon, widespread across Eurasia but rare and local in North America. All plumages have white “hip patch” usually visible on swimming birds. Breeding plumage striking with gray head, white-checkered back, and bold white lines on sides of neck. Nonbreeding plumage has fairly extensive white on face and an even border between gray and white on the neck. Smaller and sleeker than Common Loon. Larger and darker than Red-throated Loon, with straight, dagger-like bill. Especially similar to Pacific Loon, which overlaps mainly from Alaska to Japan; rarely further south along the West Coast of North America. Arctic is subtly larger-billed and often holds its head at a slight upward angle. In breeding plumage, Arctic has a darker gray nape and bolder white stripes on the neck than Pacific. Breeds on lakes in the taiga and tundra. Winters mainly on coastal bays and inshore waters; singles rarely occur on reservoirs and larger lakes.