Waterways bosses say someone may be taking “pot shots” at swans, after a female abandoned her nest.

Two female swans and a male had been sighted on the Leeds-Liverpool canal near the Pilkington Bridge in Clayton-le-Moors, but one went missing last week, feared killed.

The two remaining swans are reportedly showing signs of injury and distress.

Clive Hart, of Clayton’s area management team, said that shotgun fire had been heard down by the canal within the last few weeks.

The remains and white feathers from a bird have also been discovered in nearby woodland, although tests on the carcass have shown it to be a goose. A black and white muscovy duck has also disappeared.

And there have been reports of grisly messages posted on social networking sites boasting of killing and eating one of the Queen’s birds.

Clive said: “One of the swans has gone missing and the nest has been abandoned with eggs still in it. A swan sitting on a nest would not leave it and if a fox had taken it you would expect a carcass to turn up. The inference is that somebody has been up and had a pot shot.”

Two summers ago there were more claims of people shooting at swans, and it is just three weeks since several ducks had to be rescued by the RSPCA after 25 gallons of diesel were dumped further up the canal at Enfield Wharf.

Clive added: “We think two years ago it was air rifles but this time there have been reports of shotgun fire on the canal bank. We have heard loud bangs on the canal but we thought it cannot be as its over the canal way. The year before last one went missing and the others were ill.

“It looks like whatever happened years ago has happened again, but my view is that somebody has had a good go at the birds up there.”

Jim Swindells, of British Waterways, said: “If someone is firing a gun down by the canal we will involve the police. If anyone has any information and it’s definitely leading to a prosecution, that’s what we want. If you see anything suspicious ring British Waterways or the RSPB.”