Three swans were shot and killed in flood waters near the Leeds-Liverpool Canal, while a fourth was badly injured.

They were all victims of a high-velocity rifle, say the RSPCA which is investigating the killings.

The bloodied bird, which was found staggering about, was so badly injured it had to be put down.

Inspectors spotted the birds, which they believe had been grazing on flooded fields next to the canal, between Skipton and Gargrave.

Each of the mute swans had extensive wounds on their bodies and one had also been shot in the neck. The live bird was taken to a vets where it had to be put down.

RSPCA Inspector Dave Holgate said he and a colleague spotted the birds lying in the field on Wednesday and went to investigate in case they were victims of bird flu.

He said: "This is a shocking case of deliberate, targeted cruelty with a terribly tragic outcome. I can barely imagine the suffering these swans endured.

"Sadly this is indicative of what is seemingly a rising tide of violence against wildlife.

"Attacks of this kind are becoming more and more common and we're only treating a small percentage of the many animals that are affected."

Last year, a swan on the Leeds-Liverpool Canal at Rodley, Leeds, was hit by a two-foot long arrow from a longbow and survived after treatment.

Insp Holgate said: "A lot of injured animals will hide away to die painful and lingering deaths as entry wounds are often difficult to detect by the untrained eye.

"If anyone has any information about who may have done this I urge them to contact the police or RSPCA immediately.

"The sooner we get to the bottom of this horrific crime the better."

If caught, the culprits will be prosecuted and if found guilty face up to six months in prison and/or up to a £5,000 fine, he said.

Anyone with information should contact the RSPCA cruelty and advice line on 0300 1234 999. Calls are in confidence.

All wild birds, including swans, are protected under the Wildlife And Countryside Act 1981.