When Diana Davies was a child she often read a story about a swan, little knowing the tale would later inspire her to play a leading role in protecting swans.

Mrs Davies, 66, of Goring-on-Thames, is a founder member of the swan rescue charity Swan Lifeline, which operates in the Thames Valley. She is one of six volunteers scattered across the county.

She said: "There is something very magical about swans. Maybe it's because they look at you in such an intelligent way. They are so beautiful but also extremely vulnerable."

Mrs Davies has a collection of photographs showing the injuries suffered by swans, many of them cygnets. One shows a swan's neck stripped of feathers after being skinned by fishing line, discarded at Pangbourne.

Though she has seen the photographs many times, her distress is visible.

"This should never have happened", she said.

"We couldn't save this one. It's heartbreaking when you find them like that."

Swan Lifeline, which aims to save sick and injured swans, was founded in 1986. The charity's patron is Kidlington-based entrepreneur Sir Richard Branson.

Swans from all over the Thames Valley region are taken to the charity's rescue centre, at Eton, for treatment.

Only people from swan rescue charities, or the RSPCA, are advised to touch swans because swan-handling involves specialist techniques.

This year got off to a busy start with the charity's hotline taking a number of calls every day from people concerned about swans stuck in ice.

Water in locks across the county, including those at Osney, in Oxford, and Goring, froze just before New Year, leaving swans, cygnets, and ducks with severely restricted territory.

When birds are caught in ice, they can harm themselves while trying to escape.

Though it is unlikely they could freeze to death, they find the experience, which can go on for hours, extremely disturbing.

Ice is not the only hazard swans can face.

During the summer, swans are in danger from discarded fishing lines, floats and hooks. Particular troublespots are at Port Meadow, Oxford, and Pangbourne.

Joan Shearer, another founder of the charity, said it was not dedicated anglers who were fault. She said fairweather anglers, many of them children, could put swans at risk during the summer holidays.

She said: "We are working hard to get people to think that little bit further forward when they go fishing.

"A piece of fishing line, or a hook, can cause fatal harm to a swan. The line can get wrapped around their tongue and bill, making feeding virtually impossible.

"We have seen some heartbreaking sights. Some swans we try to rescue simply cannot be saved."

Volunteers are also called out when swans are spotted by the roadside, as the birds can mistake stretches of wet road for watercourses. Volunteers also intervene in territorial fights between rival cobs. Without intervention, the birds could fight to the death.

People who see a swan in distress or danger, anywhere in the county, can call the Swan Lifeline hotline, which is staffed 24 hours a day.

Volunteers are then called to see what they can do to rescue the swan. If they are unable to help, for example, if the swan is too far from the river bank, they call on other organisations for assistance.

To report a swan in distress, or to find out about becoming a member of Swan Lifeline, call 01753 859397. The charity also runs the Support a Swan scheme. A swan can be adopted for £10. For more information call the number above, or visit www.swanlifeline.org.uk