White-tailed eagle only from the mainland. Also Rùm hosts large seabird colonies that make for viable prey, including eider, shag ("Phalacrocorax aristotelis"), auks and gulls; as well as one of the few in Britain of manx shearwater ("Puffinus puffinus"). Furthermore, mainly as a source of carrion, were a population of around 1500 red deer and 200 feral goats; otters and gulls were also numerous and available to kleptoparasitize. The birds to be used for reintroduction were gathered as nestlings from western Norway, as this is the nearest native breeding population. The young eagles were either kept in high grade fowl cages or
Wedge-tailed shearwater (in common with the other shearwaters) as an adaptation for swimming. This species is related to the pan-Pacific Buller's shearwater, which differs much in colour pattern, but also has a wedge tail and a thin black bill. They make up the "Thyellodroma" group, a superspecies of the large shearwaters that were for a long time included in the genus "Puffinus". Wedge-tailed shearwaters feed pelagically on fish, squid and crustaceans. Their diet is 66% fish, of which the most commonly taken is goatfish. It was thought that the species mostly took food from surface feeding, observations of feeding wedge-tails suggested that