Swans die at Portsmouth's Baffins Pond nature reserve

Swans were found dead at Baffins Pond in Tangier Road, Portsmouth

A number of swans have died and another has been found with a plastic ring from a bottle stuck in its beak at a nature reserve.

Portsmouth City Council said the cause of deaths of the birds at Baffins Pond was unknown.

Two remaining swans, one of which had the plastic stuck in its beak, have been moved to a sanctuary.

The council said it would monitor the site daily and added it had sent water samples to be analysed.

Visitors have been asked not to feed birds at the pond while the deaths are being investigated, and dog owners have been advised to keep their pets on leads to prevent any contact with the water.

The council, which said it did not keep records of exactly how many swans were at the site, also reminded members of the public about the impact of litter on wildlife.

A cygnet had a plastic ring from a bottle embedded in its beak removed, which would have affected its feeding

Ben Dowling, cabinet member for culture, leisure and economic development, said there was "nothing obviously wrong" at the pond and the authority was awaiting the results of the water samples and advice on how to improve the situation.

"I'm pleased they were able to help the cygnet by removing the plastic ring from its beak but it's terribly disappointing that we're still having to tell people, 'don't drop litter'," he added.