Skellig Michael classified as a Special Protection Area in 1986, when they were recognised for containing both an usually large variety and population of birds. It is known as an eyrie for Peregrine Falcon. Other birds of interest include Fulmar, Manx shearwater ("Puffinus puffinus"), Storm petrel, Gannet, Kittiwake, Guillemot and Atlantic Puffin. A herd of goats lived on the island until recently, and it supports a population of rabbits and house mice, both relatively recent introductions, probably introduced in the 19th century by lighthouse attendants. Grey Seal haul out on the island's ledges. The word "Skellig" derives from the old Irish word
Audubon's shearwater homogeneous north-western Indian Ocean range, but not in the ecologically more diverse and by far larger Pacific range of "dichrous". These unresolved problems notwithstanding, this clade – possibly including the preceding one – has been proposed to constitute a separate species, the tropical shearwater or Baillon's shearwater, "Puffinus bailloni". These taxa could not be included in the most recent studies due to lack of material. The case of "gunax" seems fairly straightforward – as certainly as this can possibly be said in the absence of new data, it belongs to the "bailloni" clade either as a distinct subspecies, or, more