Great black-backed gull stomach contents of great black-backed gulls was made up of birds, while a further 17% of stomach contents was made up of tern eggs alone. Adult or fledged juveniles of various bird species have also been predaceously attacked. Some fully-fledged or adult birds observed to be hunted in flight or on the ground by great black-backed gulls have included "Anas" ducks, ruddy ducks ("Oxyura jamaicensis"), buffleheads ("Bucephala albeola"), Manx shearwaters ("Puffinus puffinus"), pied-billed grebes ("Podilymbus podiceps"), common moorhens ("Gallinula chloropus"), terns, Atlantic puffins ("Fratercula arctica"), coots ("Fulica" ssp.), glossy ibises ("Plegadis falcinellus"), rock pigeons ("Columba livia") and even predatory birds
Muttonbirding on 36 islands, known as the Titi or Muttonbird Islands, around Rakiura (Stewart Island), is managed entirely by Rakiura Māori. There is some evidence that this harvest has been occurring since at least the 17th century. Muttonbird may refer to various seabirds, particularly petrels in the genus "Puffinus", called shearwaters, where the young birds are harvested for food and oil by being extracted by hand from the nesting burrows before they fledge. Some species are: Muttonbirding Muttonbirding is the seasonal harvesting of the chicks of petrels, especially shearwater species, for food, oil and feathers by recreational or commercial hunters. Such