The Royal Society for the Protection of Birds (RSPB) is drawing up plans that will see wind turbines constructed on its estates as part of a new green energy drive.

The move, which will see the RSPB generating power for its own buildings and selling any surplus to the National Grid, is likely to anger some RSPB members who believe wind farms pose a threat to rare birds of prey.

In the past the RSPB has opposed wind farm projects by lodging planning objections against farms it believes are a threat to wild birds and their habitats.

Most recently the RSPB lodged objections against a giant wind farm on the Isle of Lewis on the grounds that the 181 turbines proposed would have harmed protected bird life and their habitat.

Wind turbines have faced intense opposition from wildlife charities in the past who believe the construction, presence and maintenance of large turbines in often remote landscapes can harm the wildlife and habitats they rely upon.

Critics of wind farms, however, fear the society may not apply the same rigorous scrutiny to wind turbines to be sited on its own estates.

Neil Sinden, campaigns director at the Campaign to Protect Rural England, said: "We are not at all surprised that the RSPB, as an environmental organisation, is looking at how it might get more of its power and energy needs from renewable sources such as wind turbines.

"We would have concerns if they fail to pay due attention to the landscape character, sensitivity and capacity to accommodate large scale, often quite intrusive energy infrastructure."

Other critics insist wind turbines spoil the aesthetic of the landscapes where they are built, particularly as the best locations for wind have few buildings.

Constructing turbines in protected areas such as nature reserves and National Parks has been particularly controversial.

The RSPB's plans form part of its strategy to reduce the society's carbon footprint by three per cent a year by using renewable energy sources.

Details of how much energy the RSPB hopes to generate and how many turbines it will build are still to be decided, and will then have to be approved by the society's board.

A 15 kilowatt turbine, however, is already due to be built at the RSPB reserve in Rainey Marshes, Dagenham. It has the capacity to generate enough energy for six homes.

A smaller 6 kilowatt turbine is already in use on the RSPB reserve in Barnsley.

It comes just weeks after the Environment Agency, the government body charged with protecting the environment in England and Wales, also announced it was to build wind turbines on its land, including stretches of countryside alongside rivers and waterways.

Neil Kellthorn, development and projects manager at the RSPB, insisted that the society would rigorously assess any proposed site for wind turbines on its land and apply the same criteria as it does for wind farms in other parts of the country.

He said wind turbines would be used alongside other technologies such as solar power and biofuels to reduce emissions from the RSPB's buildings.

Mr Kellythorn said: "We are developing a society-wide strategy for using renewable energy on the society's reserves. We will look no less stringently at our own wind turbine sites than we do at anyone elses.

"We are mindful of the locations and the sensitive nature of most of our sites. The RSPB does not object routinely to all wind turbine sites, but does lodge planning objections against those that pose a risk to migrating birds or vulnerable populations of birds and habitats."

A spokesman for the RSPB added: "Climate change is one of the greatest, if not the greatest, threats facing wildlife over the next 100 years.

"We have to do everything we can to protect wildlife, but we must not site renewable energy on sites that will be damaging to wildlife as any potential gain in climate change will be offset by local difficulties."