LONDON -- Thanks to a very wet English summer, the swans on the River Thames are being left in peace.

The annual census of the swans, known as "Swan Upping," has been canceled because of swollen, fast-flowing stretches of the river.

The Swan Marker's Office said Tuesday that its hopes of carrying on with a partial census had been abandoned, following cancellation of the traditional opening day on Monday.

Queen Elizabeth II retains the right to ownership of all unmarked mute swans in open water, but since the 15th century the monarch has shared ownership with Worshipful Company of Vintners and the Worshipful Company of Dyers.

The Environment Agency has posted "strong stream" warnings for many stretches of the river including one area near Windsor Castle.