The raptors would get sliced up by the blades on the roughly 5,400 turbines in Altamont Pass, or electrocuted by the wind farm's power lines. Scientists, wildlife agencies and turbine experts came together in an attempt to solve the problem. The result?

Protective measures put in place in an effort to reduce deaths by 50% failed. Deaths in fact soared for three of four bird species studied, said the Altamont Pass Wind Resource Area Bird Fatality Study.

The slaughter at Altamont Pass is being raised by avian scientists who say the drive among environmentalists to rapidly boost U.S. wind farm power 20 times could lead to massive bird losses and even extinctions.

New wind projects "have the potential of killing a lot of migratory birds," said Michael Fry, director of conservation advocacy at the American Bird Conservancy in Washington.

Wind projects are being proposed for the Texas Gulf, the Atlantic Coast, the Great Plains and Upper Midwest. President Obama said in April that he would allow turbines along the Atlantic as one way to help meet a goal by environmentalists and the industry of generating 20% of the nation's electricity through wind by 2030.

Currently about 1% of U.S. power comes from wind, according to the American Wind Energy Association.

"There's concern because of the scale of what we're talking about," said Shawn Smallwood, a Davis, Calif., ecologist and researcher. "Just the sheer numbers of turbines we're talking about - we're going to be killing so many raptors until there are no more raptors, in my opinion."

Working on the problemWorking on the problem

Interior Secretary Ken Salazar is aware of the problem and says the administration is working with energy companies and wildlife groups to help lessen the deaths.

"I think we will be able to minimize the number of birds being killed, just in terms of sheer numbers," Salazar said. "The fact that some birds will be killed is a reality."

Officials in the wind energy industry say migratory birds and birds of prey, including eagles, are killed each year at some of the nation's biggest wind farms, but they say the concerns are overstated.

Laurie Jodziewicz, manager of siting policy for the American Wind Energy Association, said the industry has taken steps to reduce bird deaths.

"We have hundreds and hundreds of projects all over the country that are not having those impacts," she said, referring to Altamont.

Bird deaths cannot be completely eliminated, she said. "There will be some birds that are killed because they do collide with so many structures," she said.

Salazar said new technology in the design of turbines and more careful placement, such as outside of migratory paths and away from ridgelines, can reduce bird deaths.

Fry says other methods include using radar to detect and shut down turbines when migratory birds approach, building towers higher and with more space between them, and placing them away from areas where raptors hunt for small animals.

"Technology has evolved over the last several decades in significant ways," Salazar said. "We know how to do wind farms in ways that minimize and mitigate the effect on birds and wildlife."

Non-wind utilizes fined heavily

Some see a double standard for wind farms.

ExxonMobil pleaded guilty in federal court in August to the deaths of 85 birds at its operations in several states, according to the Department of Justice. The birds were protected by the Migratory Bird Treaty Act, and Exxon agreed to pay $600,000 in fines and fees. In July, the PacifiCorp utility of Oregon was ordered to pay $10.5 million in fines, restitution and improvements to their equipment after 232 eagles were killed by running into power lines in Wyoming, according to the U.S. Fish and Wildlife Service.

That is far fewer than the estimated 10,000 birds (nearly all protected by the migratory bird law) that are being killed every year at Altamont, according to Robert Bryce, author of Gusher of Lies: The Dangerous Delusions of "Energy Independence."

Salazar said he expected his department's Fish and Wildlife Service task force will recommend guidelines for wind farms that are friendlier to birds.

Bird advocates raise doubts about the impact, because the guidelines are voluntary. "It's still entirely up to power companies where to place towers," said Gavin Shire, spokesman for the American Bird Conservancy.