Dog owners are advised to keep their pets on a lead
A new swan watch scheme is under way in Cheltenham to keep an eye on new cygnets born in Pittville Park.
In 2007 all eight young mysteriously disappeared. This year's cygnets are believed to have hatched but have not been seen.
The borough council's community parks' rangers are calling on local residents for their cooperation.
Wayne Sedgwick said: "We need to protect these cygnets, and members of the public have a vital role to play."
There is only one breeding pair of swans which have lived at Pittville Park for some years. They are a popular attraction for families visiting the lakeside.
"We do not know why this happened last year, or how, but if anybody sees or hears anything regarding our cygnets could they please call and let us know," said Ranger Sedgwick.
Dog walkers are being asked to keep their pets on a lead and out of the water during the breeding season as the male swan will be guarding his young.