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
Bryan's shearwater Bryan's shearwater The Bryan's shearwater ("Puffinus bryani") is a species of shearwater that may occur around the Hawaiian Islands. It is the smallest species of shearwater and is black and white with a bluish gray beak and blue tarsi. First collected in 1963 and thought to be a little shearwater ("Puffinus assimilis") it was determined using DNA analysis to be distinct in 2011. It is rare and possibly threatened and there is little information on its breeding or non-breeding ranges. It is named after Edwin Horace Bryan Jr. a former curator of the B. P. Bishop Museum at Honolulu. On