Given the migratory nature of most swan species, identifying which are native or naturalised to where the Blessed Isles can be difficult for the lay person. This difficulty increases somewhat when taking the Otherworld into account as all swan species appear to be somewhat inquisitive where the boundaries are concerned and there are Ranger records that suggest the ornamental introductions have self-supporting flocks (without spirit forms) in the Otherworld.
The native species are the mute (Cygnus olor), the whooper (Cygnus cygnus) and the berwick (Cygnus bewickii) swans, classic white swans that are considered the property of the Crown – with some wags even suggesting that the Swan Knight had a hand in the British royal lines. Related species such as the trumpeter (Cygnus buccinator) and the whistling (Cygnus columbianus) swans that usually winter in the Americas can detour on their way south from the Arctic and are also white swans said to belong to the Crown. The most commonly seen naturalised species is the Australian black swan (Cygnus atratus), widely introduced on country estates to get around the need for royal permissions. Other species may be observed at a number of zoos and wildlife refuges but are not widespread and there are no reports of them being observed in Otherworld.
Spirit forms of white swans have been observed but there has been no clear identification of which extent species they belong to – or even whether some of the observed swans are actually alternative species either extinct or unseen in our reality. Their spirit forms are usually described as very fair in colouring, very slender and very quiet.
The majority of folk-tales about swans are simple variations of typical European stories, most often of siblings cursed with a swan-shape or an animal wife. The pinnacle of this story-telling is the Swan Knight but it is also recognisable in the Children of Lir (not related to Lir / Llyr, Bran or Manannán). However, there is a distinctive Blessed Isles touch to the use of swans to indicate the Otherworldly fair folk.