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
Persian shearwater off Oman and Socotra, Yemen, while "P. p. temptator" has been estimated to number fewer than 500 pairs on Moheli Island in the Comoros (reviewed by Brooke 2004). It is thought likely that more breeding colonies lie undiscovered elsewhere in the northern Indian Ocean (Onley and Scofield 2007), thus the total population probably includes more than 10,000 mature individuals. The population trend is believed to be downwards. Persian shearwater The Persian shearwater ("Puffinus persicus") is a seabird in the family Procellariidae formerly lumped in with Audubon's shearwater ("Puffinus lherminieri"). There are two listed subspecies of the Persian shearwater: After breeding,