Wardens get down to the task of swan-upping

It might not be quite up there with the Changing of the Guard, but it's certainly one of Britain's most venerable royal customs. The annual pageant of swan-upping - counting the swans on the middle reaches of the river Thames - got under way yesterday, amid fears that attacks by vandals are taking an increasing toll on the birds.

Historically, all unmarked mute swans on open water belong to the Crown, a tradition dating from the Middle Ages when they were hugely prized for their meat. Roast swan was the favourite dish of Chaucer's monk in The Canterbury Tales, and was often the centrepiece of royal banquets.

Tastes change; now we have the turkey, and eating such graceful birds seems unthinkable (although some who have eaten it say the meat is delicious).

But while swans no longer end up on the royal table, the Queen continues to exercise ownership rights to them on the Thames and its surrounding tributaries upstream of London as far as Abingdon in Oxfordshire, and the annual counting by specially appointed royal officials continues to this day.

Led by the Queen's Swan Warden and the Queen's Swan Marker, the swan uppers, a team of watermen from the Dyers' and Vintners' livery companies of the City of London, wear scarlet uniforms and fly flags as they make their five-day journey up the river in a flotilla of traditional rowing skiffs to count this year's cygnets, starting from Sunbury-on-Thames, upstream of Hampton Court palace.

The Swan Warden, a scientific and non-ceremonial role currently held by a leading academic ornithologist, Professor Christopher Perrins of Oxford University, will ring each cygnet with an individual identification number. Cygnets will be weighed and measured to obtain growth rates and birds will be examined for any sign of injury.

The ceremony, thought to date from the 12th century and carried out during the third week of July every year, was previously continued merely to keep a colourful tradition alive. In recent years it has become an important tool for experts to assess the impact of modern threats such as shooting, vandalism and becoming entangled in discarded fishing tackle, as well as more natural hazards such as minks and foxes.

While experts believe overall there has been an increase in the number of breeding pairs, but attacks, particularly shootings, have been rising. "Regrettably, swans and cygnets continue to be subjected to vicious and mindless vandalism with devastating, and often fatal, consequences," said the Queen's Swan Marker, David Barber. "And eggs continue to be destroyed by senseless youths." Mr Barber's duties include monitoring the health of the local swan population and giving advice on their welfare to organisations up and down the country. He also supervises the rescue of sick and injured birds and removes them from stretches of the river used for rowing regattas.