great northern diver

From the fact that the species is a diver, the largest or greatest of those regularly found off the British Isles, which has a very northerly range (no further south than the British Isles).

great northern diver (plural great northern divers)

1. (Britain, Ireland) A large member of the diver family, Gavia immer, commonly breeding in North America, where it is known as the as common loon.

• common loon
• great northern loon