Very rare migrant from High Arctic. Usually seen as single birds on ocean waters, at times in harbors. Like other loons (divers), feeds by diving and can cover long distances underwater. All plumages like much commoner Common Loon (Great Northern Diver), but bigger bill of Yellow-billed is more sharply angled up and, as the name suggests, overall ivory-yellow in color. Bill of Common Loon can appear very pale in some lights, but has dark line along top all the way to the tip, vs. pale creamy tip on Yellow-billed.