The annual count of Queen Elizabeth II's mute swans has begun amid worries that dog attacks may have taken their toll on the monarch's waterfowl in the River Thames.

The queen is the traditional owner of unmarked mute swans, and royal custom requires they be counted each year in a colorful affair.

The tally began on Monday when royal scarlet-clad Swan Uppers rowed up the River Thames outside London in a flotilla of wooden skiffs to count and examine cygnets, or young swans, for disease and injuries.