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
Christmas shearwater subalaris"). The Christmas shearwater is a slender-bodied shearwater, about 36 cm long, with a wingspan of around 75 cm, and weighs around 350 g. It has dark plumage all over, generally blackish-grey with a rusty-brown tinge, slightly paler on the underside of the bird, and with some small edging of white under the chin and pale fringes to the upperwing coverts. It has brown-grey feet and a dark bill and eyes. Both sexes are alike, as are the young after fledging. Nestlings are covered in dark grey down feathers. The species closely resembles the sooty ("Puffinus griseus") and short-tailed shearwaters