The swan is unusual in that it has been a Royal bird since at least the twelfth century, and all swans at liberty on open or common waters belong to the Crown by right. The Crown has granted the privilege of keeping swans on common waters provided that they were pinioned and marked. However, if a bird strayed and was not recaptured within a year and a day, ownership passed back to the crown.
Swans were kept for a variety of reasons. As a Royal bird they were highly valued and created an air of distinction. They made highly prized gifts and were customarily eaten at Christmas and at banquets. As they were cheap to rear they could easily be turned to profit through sale.
The swan's royal status was formally enshrined in the Act of Swans which came into force in 1482. The Act provided formal legislation concerning the ownership and marking of swans. Swan marking was necessary, as with other animals, to distinguish ownership. Swan-Marks were essentially in the form of scars. Upper bill marks were the most common, with less common marks being made on the lower bill, leg, foot or wing. Beak marks on the upper or lower bill were produced by cutting with a sharp knife, creating a scar. Once legally obtained by grant or prescription from the crown, the Swan mark together with the 'game' of swans marked with it became the absolute property of the owner. Swan Rolls were kept to record each mark and the name of the owner.
In June 1999 Christies auctioned the earliest known swan roll, dating from the 1500's. It listed 99 different marks made on swan bills in the Broadlands of Norfolk and Suffolk. Although it was bought by an overseas purchaser, an export ban allowed the Norfolk Record Office time to raise the amount of the purchase price and keep the document in the country. A photograph of part of the document in the Sunday Telegraph of the time appears to show a swan mark for the Jermy family .....
Refs: Greg Neale. 30 May 1999. Medieval swan-mark scroll goes to auction. The Sunday Telegraph. Page 14, Columns a to h.