The term 'large waterbird' can be summarized by two crossword solutions: SWAN (4 letters) and GOOSE (5 letters). Swans are large, graceful birds with long necks and webbed feet. They are found in temperate climates around the world and are known for their majestic beauty. Geese are also large waterbirds, but they have shorter necks and are usually found in colder climates. They are known for their loud honking and aggressive behavior.