According to BBC News:
Swans on the River Thames are under threat from dog attacks and the American mink, the Queen’s Swan Marker has said.
David Barber said the number of cygnets were down on last year as his team began an annual population survey.
Mr Barber said: “We’ve had a pretty rough time with…dog attacks, all sorts of things – like mink.”
“They’re not indigenous to this country and they’re breeding like mad on the river here, and they do take a lot of young cygnets,” he added.
American mink are thought to have escaped into the wild from farms decades ago.
