The Law of Unintended Consequences: Scores of golden eagles killed by wind turbines

The environmental impact of wind turbines - the problem with bird collisions of many species has been known for many years.

California's attempts to switch to green energy have inadvertently put the survival of the state’s golden eagles at risk.

Scores of the protected birds have been dying each year after colliding with the blades of about 5,000 wind turbines.

Now the drive for renewable power sources, such as wind and the sun, being promoted by President Obama and state Governor Jerry Brown has raised fears that the number of newborn golden eagles may not be able to keep pace with the number of turbine fatalities.