WATCH: Royal swan counters take to the River Thames to count the queen's swans

Cape Town – Every year royal swan counters take to the River Thames for the British tradition of swan upping – an event dating back to the 12th century.

The five-day journey upriver is held to teach the community about the proper conservation of the swans, while checking their health.

“A flotilla of traditional Thames rowing skiffs, manned by Swan Uppers in scarlet rowing shirts and headed by The Queen’s Swan Marker, wearing a hat with a white swan’s feather, row their way steadily up the Thames,” explains the official website for the British monarchy.

“‘All up!’ they cry as a family of swans and cygnets is spotted, and the Swan Uppers carefully position their boats around the swans, lift them from the water and check their health.”

Back in the 12th century, the swans were served as a delicacy on holidays but are now considered royal birds to be protected and conserved.

And while ownership of swans today is only determined by their parentage, the Queen reserves the right to claim any unmarked swan swimming in open waters.