Until recently thought to be a form of the Old World's Arctic Loon (Gavia arctica), the Pacific Loon is well named, for nearly all of these birds winter along the Pacific Coast of North America except for a few birds that delight birders by appearing at scattered locations along the Atlantic seaboard. In the east, it is the rarest and least known of the three loons found there. More social than other loons, this species frequently gathers in large flocks. On the northern breeding grounds adults often fly many miles between their nesting ponds and suitable feeding areas. It usually feeds closer to shore than other loons; its diet consists mainly of fish, but on the breeding grounds it also takes crustaceans.