New Delhi, July 8 -- Scarlet uniforms flashed against the riverbank. Wooden skiffs glided in formation. A young swan, gently lifted from the water, was measured, inspected and released.

The annual five-day census of swans belonging to King Charles III - known as Swan Upping - began Monday on the River Thames to assess their health.

One of the British monarch's less-known titles is Seigneur of the Swans - Lord of the Swans - and according to ancient lore, he or she owns all members of the mute swan species found in Britain's open waters.

Every year, a team of carefully selected oarsmen - Swan Uppers - are tasked with finding the swans on a stretch of the Thames.

When a family is spotted, they shout, "All up!" and the boats quickly surr...