The white-tailed eagle is one of Europe's largest birds of prey

The RSPB says nine white-tailed eagles have been killed on the Smola islands off the Norwegian coast in 10 months, including all of last year's chicks.

Chick numbers at the species' former stronghold have plummeted since the wind farm was built, with breeding pairs at the site down from 19 to one.

Scientists fear wind farms planned elsewhere could also harm birds.

And there are fears Britain's small population of the birds could be adversely affected.

The impact of wind farms has long been a concern or ornithologists

 Fewer chicks

The number of chicks born each year at the site has fallen from at least 10 to three last year, with births outside the borders of the site falling too.

Only one chick is expected to fledge from the site this year.

Smola, a set of islands 10km (six miles) off the north-west coast of Norway, was designated an Important Bird Area by Birdlife International in 1989 because it had one of the highest densities of white-tailed eagles in the world.

Scientists now fear wind farms planned for the rest of Norway could have a similar impact on the birds.

RSPB conservation director Mark Avery told BBC News more care needed to be taken when choosing a site for wind farms. He said: "The problem is if wind farms are put in stupid places where there are lots of vulnerable birds and lots of vulnerable rare birds."

He said most wind farms would not cause any harm to birds but that the Smola wind farm had been badly sited in a place where it put white-tailed eagles at risk.

He added: "It seems these birds are flying around a lot of the time and they're colliding with the wind turbines and being killed in big numbers.

"So this colony that is very important - was very important - has been practically wiped out because this wind farm was built in exactly the wrong place."

Careful planning urged

The RSPB says it supports renewable energy, including wind farms, as a way of tackling climate change, which it sees as the biggest threat to wildlife.

But it is urging developers and governments to take the potential impact on wildlife such as eagles properly into consideration when planning new wind farms in future.

Researchers are now running weekly checks for dead birds at the 68-turbine Smola site, with both conservationists and the wind farm operator calling on the Norwegian government to improve its environmental impact assessments of such sites.

And the Norwegian Institute for Nature Research has launched a four-year study at the site to assess the impact of the turbines on various species of birds and the ability of white tailed eagles to adapt to them.

Meanwhile, Statkraft, which operates the Smola site, says it is doing everything it can to find a solution to the problem.