Wind turbines turning gracefully in the breeze have become an icon of green energy and sustainable living across the world.
But some researchers claim that wind turbines kill birds like eagles, hawks and other birds by the thousands every year -- and many of these birds are federally protected or endangered species, like the California condor and the bald eagle, America's national bird.
Do wind farms kill birds, or is that just a lot of hot air?
California Condors: Soaring and Plunging
The California condor (Gymnogyps californianus) is a magnificent soaring vulture with a wingspan of 10 feet or more. One of the largest birds in the world, it can live up to 60 years -- if it's lucky.
But bad luck seems to be the only luck the condor has: Its population in the American West has plunged in the last 50 years due to habitat destruction, lead poisoning and hunting. In the 1980s, there were an estimated 22 specimens left alive in the wild, and extinction seemed imminent.
Careful wildlife management and strict laws against killing the California condor enabled the birds' numbers to rebound. But now, another threat looms over the birds: wind turbines.
The U.S. Bureau of Land Management (BLM) is granting the wind energy company Terra-Gen Power a 30-year easement to put a large cluster of wind turbines on BLM land in Southern California's Mojave Desert -- prime habitat for the condors.
Do Wind Turbines Kill Birds?
There's a large and growing body of evidence suggesting that wind turbines kill thousands of birds every year.
According to research published in the Wildlife Society Bulletin, wind farms are responsible for killing about 573,000 birds every year in the United States. Many of the birds killed are raptors like eagles, hawks, falcons and other large birds.
The blades on wind turbines appear from the ground to be moving at a slow, lazy pace, but the tips of the blades can reach speed of 170 miles per hour or more -- fast enough to chop off an eagle's wing.
An Associated Press investigation found that the ground around wind farms are frequently littered with dead and severely injured birds.
"Some of the most iconic and vulnerable American birds are at risk from wind industry expansion unless this expansion is carefully planned and implemented," the American Bird Conservancy states on its website. "Onshore, these include golden eagles, whooping cranes, sage-grouse, prairie-chickens, and many migratory songbirds. Offshore, brown pelicans, northern gannets, sea ducks, loons, and terns are at risk, among other birds."
Birds vs. Wind Energy: A Political Hot Potato
To further complicate matters, critics are charging the Obama administration with giving wind farms a pass when they kill a federally protected species like the bald eagle, while other companies must pay fines in the millions for the same killings.
The California condor is a case in point: The New York Times reported that Terra-Gen Power will face no fines if they kill a condor on its wind farm, a move that has outraged wildlife advocates.
"Allowing the legal killing of one of the most imperiled birds in the United States threatens endangered species conservation efforts across the country," the American Bird Conservancy said in a statement.
"American Bird Conservancy supports wind power when it is bird-smart, and believes that birds and wind power can co-exist if the wind industry is held to mandatory standards that protect birds."
Can Birds and Wind Turbines Just Get Along?
Proponents of wind energy have offered a range of solutions to reduce the killings of birds at wind farms. Siting wind turbines away from prime raptor habitat to reduce the likelihood of collisions with eagles and hawks is a relatively easy alternative.
And newer designs of wind turbines -- with a vertical axis and/or no lattice-work structure (which attracts birds of prey) -- should virtually eliminate the chance of a bird-turbine collision.
According to some reports, these mitigation strategies are already working at places like California's Altamont Pass, home to one of the largest wind farms in North America, which is now seeing fewer bird deaths than in years past.