And when a a cygnet went missing from the Mill Pond in Ifield, all that was found of it was a grisly torn off leg.

John Potts, 61, a member of the Swans and Friends Bird Rescue society, said: "On August 23 we found a male swan with a hook in its mouth, we also had a female one which was looking lethargic and we discovered she had fishing line wrapped round her tongue. She probably hadn't eaten for a week.

"And on August 18 we noticed a cygnet was missing and when we looked for it we found a leg. We think it was a dog attack or possibly a human as opposed to a fox – a fox wouldn't take just the body."

The society, which is run by volunteers and relies entirely on donations, takes any injured bird it finds to the vet to be patched up –
A Crawley Council spokesperson said: "We urge anyone who uses the Millpond for fishing, exercising their dog or just walking to take all the litter and any equipment home with them.

"It is fantastic to see swans in our lakes but selfish behaviour can cause injury to these beautiful creatures and misery to those who get joy from seeing them."