A £350 reward is being offered to anyone who can help catch the vandals who caused the death of four cygnets by dumping vegetable oil in Peatmoor Lagoon.

Roger and Sue Hulbert, who run the South West Swan Sanctuary in Shrivenham Road, Swindon, are still feeding the parent swans which survived after they were found smeared in oil last week.

The National Swan Sanctuary and Swindon Services are offering the reward.

Mr Hulbert, 57, said: "The swans have changed. They are quiet and reluctant to go in the water. But when the swans are on land, they are in danger of being attacked by dogs."

After cleaning the oil from the swans' feathers, Mr Hulbert helped his wife coax them onto an island in the lake, beyond the reach of vandals.

John Short, director of Swindon Services, said: "We would urge anyone who has information that could help us trace the cause of this atrocious vandalism to get in touch with us as soon as possible."

Anyone with information should contact Martin Hambidge on (01793) 463000.