A five-year-old girl had the audacity to ask something unspeakable of the Queen: permission to keep a swan for a weekend.
The Queen has asked me to thank you for your letter... from which Her Majesty has taken careful note of your comments regarding the keeping of swans as pets. I should perhaps explain that it is a common misconception that The Queen owns all the swans in the United Kingdom. Her Majesty owns mute swans and only exercises her right of ownership over swans on certain parts of the River Thames. It should be remembered that as native wild birds, swans now enjoy statutory protection under the Wildlife and Countryside Act 1981. The Queen was encouraged to know of your interest in our native birdlife and thought it kind of you to write as you did.
Owning unclaimed mute swans in open water in both England and Wales is law that dates back to Medieval times. Each year the swans are health checked and weighed. The British Monarchy’s website explains:
The swans are also given a health check and ringed with individual identification numbers by The Queen’s Swan Warden. The swans are then set free again.
This allows her Majesty's Swan Marker to give researchers data to monitor the swans' health.