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
Chagos Archipelago fuscata"), brown and lesser noddies ("Anous stolidus" and "Anous tenuirostris") wedge-tailed shearwaters ("Puffinus pacificus") and red-footed boobies ("Sula sula"). Land bird fauna is poor and consists of introduced species and recent natural colonisers. Red fody had been introduced and now widespread. Environments of Chagos Archipelago provides rich biodiversity and support varieties of cetacean species within the vicinity, such as three populations of blue whales and toothed whales (sperm, pilot, orca, pseudo-orca, risso's and other dolphins such as spinners, and so on). Dugongs, being locally extinct today, once thrived in the archipelago and the Sea Cow Island was named after the