Stockton river warning after 20 swans found dead
People are being warned to keep their pets away from part of the River Tees in Stockton, UK, where 20 swans have been found dead.
A stretch of the river near Moat Street is being monitored following the deaths of the birds since 28 July.
Stockton-on-Tees Borough Council said it was strongly suspected to have been caused by avian botulism, which could caused by the recent hot weather.
People are also being advised to keep away from any dead or distressed birds.
Councillor Steve Nelson, said: "We're saddened by the deaths of the swans and are asking people to take a few precautions.
"Obviously, the first is to stay out of the water yourself - we strongly advise this at all times anyway but this is just another reason to do so, alongside the other dangers like currents and cold water shock.
"If you're walking your dog close to the area where the swans have died, we're advising you to keep them on a short lead and away from the water."
The council is asking people not to feed any of the swans or any other birds at the site because it can add organic material to the water, which can make the problem worse.