Every year for five days, all the swans and young cygnets belonging to Queen Elizabeth II are counted, checked and tagged along the river Thames. The census is referred to as "swan upping."
No one knows for certain when the ceremony first began, according to the event's official educational brochure, but the earliest written record of the swan as a royal bird dates to 1186. Originally the event was a ritual to keep track of breeding stock and to ensure there were sufficient birds for feasting, but now the process is more about conservation, reports The Guardian.
"Today the English crown retains the right to ownership of all unmarked swans in open water, although in practice this privilege is only exercised by the queen on certain stretches of the Thames," Reuters reports.
Now swan upping takes place annually the third week in July. Dressed in scarlet red uniforms, swan uppers ride down the river in wooden skiffs until they locate a brood of mute swans (a species of swan). They slowly surround the birds with their boats until they can be lifted from the water. The swans and cygnets are taken ashore where they are weighed, measured and checked for disease and injury.
“We will lift the whole family out of the water, we will take them ashore, we weigh them, measure them and check them for any injuries,” David Barber, the queen’s official swan marker, told Reuters. “You have a population of swans that hasn’t changed much since the mid 1800s.”
Barber told Reuters he would be pleased if they found about 100 cygnets this year.
Now and throughout the year, injured or sick swans are rescued and cared for, then re-released after they are treated.
"Life for swans on the Thames is not easy," says the swan upping guide. Aquatic vegetation can be scarce and it is often difficult for swans to feed on the riverbank. In addition, the birds face threats from fishing tackle, overhead wires, oil pollution, vandalism, dog attacks and shootings.
Barber tells The Guardian he hopes the annual event will draw attention to threats to these young swans.
Editor's note: This story has been updated with new information since it was published in July 2017.