Swans are one of the most charismatic of birds. Their graceful flight and peaceful beauty as they glide across the water have inspired humans to find spiritual meaning in them. Iron Age Britons considered them supernatural.
Mute swans are the traditional birds of folklore. Although migratory, they became semi-domesticated in Britain by the 10th century. Although Richard the Lionhearted is often credited with bringing swans to England on his return from the Crusades in the 12th century, documents exist dating swan keeping as far back as 966, during the reign of King Edgar.
It was in the 12th century that the Crown claimed ownership of all swans, http://www.royal.gov.uk/output/page4952.asp. In the 15th century, swan ownership was shared with the Vintners’ and Dyers’ Companies. That continues today, with an annual ceremony called Swan Upping, in which cygnets, baby swans, are captured, weighed, checked for health problems, banded and released.
So Seven Swans A Swimming would have had royal as well as spiritual connotations.
Today in the U.S., migratory waterfowl are protected by state and federal laws. Permits are required to keep wild birds legally. If you are in any doubt about birds you are considering acquiring, check with the state department of fish and game, parks and wildlife or Natural Resources. This beautiful pen, a female swan, belongs to Craig Hopkins of Hopkins Alternative Livestock near Richmond, Indiana, http://www.hopkinslivestock.com/.
Mute swans are controversial residents along the East Coast, where they have displaced local Trumpeter swans, http://thechesapeakebay.com/swans.shtml, http://www.mdsg.umd.edu/issues/restoration/non-natives/workshop/mute_swan.html. Mute swans have been acquired as decorative waterfowl for parks and estates, but easily leave and become feral. To avoid those problems, the state of New Hampshire requires by law that Mute swans be pinioned, an operation done on young cygnets to remove the distal joint of the wing, making flight impossible.