Police are investigating reports that the male swan, known as a cob, had been shot and killed on the River Calder near Thornhill Road, Dewsbury.

Lindsay Emmitt, who lives on nearby Island View, said: "We've had this family of swans on the river and all the residents on Island View have been watching them since they came and built their nest, then sat on their eggs.

"Then when they all hatched we watched the babies growing. One of them strayed from the nest onto the banking, but its dad came and sat with it to make sure it was okay.

"Last week a neighbour found one of the adult swans – the dad we now think – dead at the side of the river. We think it's been shot. All the residents are distraught because they mate for life and the mum and babies are having to swim past dead dad every day."

She said a neighbour had spent hours making phone calls to try to get someone out to remove the body. She said: "Eventually, police came then the RSPCA sent a woman to remove the body – a massive, heavy, waterlogged dead swan, can you imagine?

"She couldn't get it from the river so it's still there and some animals have been at it now and loads of feathers are up the river bank. It's horrible.

"So now there's just mum and five gorgeous cygnets and we're watching out for them."

Mrs Emmitt said since the incident had been reported police had stepped up patrols in the area.

She said: "We just hope now that if anyone sees any kids, or adults, throwing things or shooting at the birds that they will ring the RSPCA or police as soon as possible and report them.

"We want the remaining family to live in peace as they give so much pleasure to people who sometimes come from afar to look at them."

A police spokesman said when officers got to the scene, the swan had been mutilated by other animals so they were unable to confirm it had been shot.

But he said investigations were still under way.