US scientists track what's killing golden eagles

More than four decades ago the golden eagle was awarded the same protections under US law as the country's national bird, the bald eagle. Even disturbing their nests is a criminal offence.

The raptor is not considered to be under threat but scientists are worried about a recent increase in the number of golden eagles killed by wind turbines. Eagles in flight tend to focus on the ground below as they look for prey, unaware of the fast-spinning blades in their paths until it's too late.

The wind energy industry says such deaths account for a tiny percentage of human-caused deaths of eagles. It says it is working with the government to help protect birds.

The BBC spent a day with a scientists from the US Fish and Wildlife Service in New Mexico who fit transmitters to the backs of eagles in an effort to find out more about their lives - and deaths.

Produced for the BBC by David Eckenrode

Altered States is a series of video features published every Wednesday on the BBC News website which examine how shifting demographics and economic conditions affect America on a local level.