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Altamont Pass wind turbines in 2006 (Photo by Claire Asher/Flickr)

Notorious Altamont Wind Area Becomes Safer for Birds

Not that it much matters, since we now know that cats are the real killers that must be stopped, but there’s good news in the long-running controversy about wind power and birds. A study of the notorious wind turbines in California’s Altamont Pass suggests that efforts to reduce the number of bird deaths from the spinning blades are succeeding.

Shutting down turbines in the winter months, removing particularly poorly sited turbines and replacing hundreds of smaller, older turbines with fewer newer, larger turbines are all cited in what researchers say has been a decline of around 50 percent in fatalities to four focal species – the American kestrel, burrowing owl, golden eagle and red-tailed hawk – since the middle of the last decade.

This study – reported on first by the San Francisco Chronicle – was completed late last year for the Alameda County Community Development Agency by ICF International, which has served as the officially monitoring team for the Altamont Pass Wind Resource Area since 2008.

Altamont was one of the first extensive wind power developments in the world, with thousands of what are by today’s standards small turbines erected beginning in the 1960s. From April to September especially, it’s a remarkable wind resource, with cool marine air from the Bay Area pulled furiously into the hot Central Valley. Raptors in particular love those winds, and when the turbines went up, it wasn’t a good mix. (See related post: “Montana Wind Turbines Give Way to Raptors.”)

Lawsuits have since brought settlements promising change, and while birds continue to die at Altamont, the new study indicates they do so in far fewer numbers than they did seven or eight years ago – in the neighborhood of the 50 percent reduction one of the settlements had sought by 2009.

The study used 1,130 as the baseline 2004 figure for the four focal species, and looked at what happened from 2005 to 2010.

“The estimate of the total number of focal species fatalities occurring during the 2010 bird year is 638 birds, a decrease of 44% from the baseline,” the study reported. “Using the 3-year rolling average from the last 3-year period, the reduction is 51%.”

The authors noted that comparing the new numbers to earlier ones is difficult, as sampling and assessment techniques have been far from consistent, and the task of recovering all carcasses over a vast terrain is a big challenge. But this latest study was far more intensive, comprehensive and systematic than any ever done, yielding “the best estimates available of total APWRA-wide avian fatalities ever produced,” the authors said.

The Golden Gate chapter of the Audubon Society, a leader in fighting to make the Altamont wind area safer for birds, called the findings “very good news.” The group said that although much work remained to be done at Altamont – particularly by NextEra Energy Resources, the largest wind turbine owner at the site – the results so far showed that “with careful siting and design, it’s possible to significantly reduce the risk to birds from wind turbines.” (See related quiz: “What You Don’t Know About Wind Energy“)

See the Golden Gate Audubon blog for a great discussion of how the group worked to force changes at Altamont and how repowering and thoughtful siting can make wind turbines less dangerous for birds.

The ICF study, a 171-page PDF, is available here.

—Pete Danko

This post originally appeared at EarthTechling and was republished with permission.