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
Puffinus and often give eerie contact calls on their night-time visits. They lay a single white egg. They feed on fish, squid and similar oceanic food. Some will follow fishing boats to take scraps, notably the sooty shearwater; these species also commonly follow whales to feed on fish disturbed by them. Traditionally, "Puffinus" has been grouped with the "Procellaria" and "Calonectris" shearwaters. However, more recent results have determined that the genus is apparently paraphyletic and while in part very close to "Calonectris", forms a clade with the genera "Pseudobulweria" and "Lugensa", which were formerly presumed to be gadfly petrels, and can