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
Dune shearwater which bred in lava fields. Extinction of the species occurred about 2000–3000 years ago, contemporaneously with the first human settlement of the islands by the Guanches, with the cause likely to be human predation. Dune shearwater The dune shearwater ("Puffinus holeae"), also known as the Canarian shearwater or Hole's shearwater, was a relatively large shearwater which bred in the Canary Islands archipelago of the North Atlantic Ocean. Fossils have also been found in the Figueira Brava cave archaeological site on the western coast of Portugal. The specific epithet honours Mrs Jean Hole who collected fossil material of the species on