Wind farms - the "environment-friendly" energy source - are threatening to push the golden eagle, one of Britain's rarest birds, into extinction.

Conservationists say that the rapid spread of the farms in Britain - encouraged by Government subsidies for renewable energy projects - poses a grave threat to birds of prey. Other species at risk are osprey, red kites, merlins, kestrels, honey buzzards, ravens and peregrine falcons.

Thousands of birds - including hundreds of golden eagles - have been killed after flying into the blades of wind turbines in the US and continental Europe.

Campaigners fear that the same is happening here, and are particularly concerned by proposals for four new wind farms in Scotland - home to almost all of Britain's 431 pairs of golden eagles. Fears were raised in January when a red kite was killed by a turbine near Aberystwyth in Wales.

The landowner behind one of the proposed wind farms is Sir Jack Hayward, the multi-millionaire former chairman of Wolverhampton Wanderers football club, who made a fortune investing in the Freeport, Grand Bahama Development, on Grand Bahama.

He is applying to build 36 turbines, each nearly 360 ft tall, on his 13,000-acre Dunmaglass estate, 14 miles south of Inverness, near Loch Ness.

Sir Jack, 80, who says in his Who's Who entry that one of his recreations is "preserving the British landscape", wants the turbines to stretch for four miles along the highest ridge of the Monadhliath mountains.

The businessman, whose fortune is estimated to be £140 million, is expected to receive payments of at least £120,000 a year for 20 years from the developers, a cost that will be passed on to electricity customers.

The project, in an area of outstanding natural beauty, has infuriated the owners of neighbouring estates, who say that the wind turbines will threaten golden eagles and damage one of Europe's wildest and most beautiful areas.

Sigrid Rausing, the owner of the neighbouring Coignafearn estate, said that the turbines could kill or drive away golden eagles, wrecking her efforts to encourage the birds.

Dr Rausing, the younger daughter of Hans Rausing, the Swedish industrial visionary who built up the Tetra Pak packaging empire and is frequently named as Britain's richest resident, has spent six years trying to restore the estate as a breeding ground for the eagles after decades in which they were poisoned and had their nests destroyed.

"We have rebuilt three of the nests and want Coignafearn to again become a home to these endangered and splendid birds," she said. A pair of golden eagles has already shown interest in one of the nests and the estate is a hunting ground for younger golden eagles.

"Birdwatchers come to Coignafearn to enjoy the landscape and the sightings of vanishingly rare birds," Dr Rausing said. "It is one of the wildest and most beautiful areas of Europe, which now may be destroyed by an energy development at the whim of an owner next door."

Coignafearn is also a haven for white-tailed sea eagles, whose "fearlessness and wing span" would make them particularly vulnerable to the turbines, said Dr Rausing, who is the founder of the London-based Sigrid Rausing Trust, which gives £10 million to charities, including environmental groups, every year.

Roy Dennis, Coignafearn's consultant ecologist, said the wind farm would "turn a pristine wilderness with unbroken views into an industrial site. The Government has gone mad".

Sir Jack, believed to be in the Bahamas where he lives for most of the year, was unavailable for comment last night. Roddy D'Anyers-Willis, the agent for his estate, rejected the complaints, saying: "I don't think the wind farm will have much effect on wildlife because wildlife adapts when these things occur."

Renewable Energy Systems, the wind farm company behind the project, said that it had carried out "comprehensive studies" led by a "highly experienced ornithological consultant" whom it refused to name. It was confident that "all wildlife issues" had been addressed. A public consultation will be carried out from next week.

The other new wind farms proposed in Scotland are at Farr, Glen Moriston and Tomatin. A spokesman for the British Wind Energy Association, which represents the industry, said there was "no need" for public concern. "Many more birds will die if we do not tackle climate change by using renewable energy and reducing carbon dioxide emissions," the spokesman said. "That is more important than the odd bird killed by a turbine."

Although no golden eagle has yet been killed by a turbine in Britain, up to 800 have died in Californian wind farms, according to the state's energy commission. Thousands of other birds have also perished. A study in Sweden found that 49 migrating birds were killed by one turbine in one night, while in Spain 6,450 birds fell victim to turbines in one year.

The Government is pushing the development of wind farms in an attempt to reach its target of producing 10 per cent of Britain's energy to come from renewable sources - such as wind, the sun and water - by 2010. There are nearly 100 wind farms, with about 1,000 turbines, in Britain today and proposals for more are are mushrooming.

Dr Rausing condemned the "obsession" with wind farms. "What mad policy is it that describes as 'green' energy that costs more in infrastructure than it will ever produce in energy, and which utterly ruins the landscape on which it is built?"