At a time when demand is rising for greener energy sources, the Altamont Pass has become one of the nation's leading producers of wind power, generating enough pollution-free electricity annually to power 120,000 homes for a year.
But the Altamont, where more than 5,000 windmills line the hilltops, has also become a death trap for thousands of migrating birds that get chopped up in fast-rotating turbine blades as they fly through or hunt for prey.
An estimated 1,700 to 4,700 birds are killed each year in the 50-square-mile Altamont Pass Wind Resource Area, and of those fatalities, between 880 and 1,300 are federally protected raptors such as burrowing owls, red-tailed hawks and golden eagles, according to a study released last year by the California Energy Commission.
"Altamont is killing more birds of prey than any other wind farm in North America," said Jeff Miller, a wildlife advocate at the Center for Biological Diversity. "Incredible numbers of raptors are being killed there, and it's hard to believe it's not having effects on the populations."
Environmentalists were once reluctant to take on an industry that provides an eco-friendly alternative to fossil fuels blamed for air pollution and global warming. But the bird deaths have prompted wildlife advocates to sue nine wind farm operators and appeal Alameda County's decisions to renew their operating permits without requiring measures to reduce bird collisions.