The Kelp/Dominican Gull or Southern Black-backed Gull is a gull that breeds on coasts and islands through much of the Southern Hemisphere. It is found around South America, parts of Australia (where it overlaps with the Pacific gull), and here in New Zealand (where it is known as the black-backed gull, the southern black-backed gull, mollyhawk or karoro). Have a read of the Wikipedia page linked above. 🙂