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.


  1. Chris
    Long Beach
    February 15, 2013, 4:50 pm

    I don’t trust these studies and numbers at all. My brother is one of the few raptor experts left in the state. He used to be a falconer in the 70s and now is hired to do raptor nest studies and population studies.
    He was stating that these wind companies most likely have people walking the fields early in the morning to get rid of the dead bird evidence. Most of this land is private so they are on the honor system with reporting blade bird strikes.
    If the real numbers were released for the protected Golden Eagles these farms would most likely be shut down.

    This does not even account for the huge numbers of raptors electrocuted each year in the U.S. from ungrounded power poles.

    The expansion of rural areas into homes has forced a lot of shy raptors to now nest in housing tracks and on buildings. I never saw Coopers Hawks, Sharp-shinned Hawks, and Prairie Falcons in our area growing up. Now I see many each year. While, I see fewer and fewer buteos in our area soaring or roosting.

  2. V-man
    February 6, 2013, 6:53 pm

    It’s a good thing that environmental protection is meeting environmental protection.

  3. Flyguy
    February 6, 2013, 12:07 pm

    How? wouldn’t they be hurt, maimed, or even killed in the windmills?

  4. Guy Earl Warmoth
    United States
    February 6, 2013, 10:49 am

    Brian of Charlotte hit the proverbial nail on the head. And thats exactly why the hills of eastern Kentucky are a war zone today. The strip mining of the coal in the Beautiful Blue Ridge has left it looking like NatGeo’s picture of a Martian Canyon. We’re talking saving birds that hit the blades. Not blasting Altamont with dynamite, and hauling out 60 million metric tons. Or fracking the place into an oil slick.

  5. Brian
    Charlotte, North Carolina
    February 5, 2013, 1:56 pm

    double-standard? hardly! the article clearly states that that particular wind energy group has reduced the number of bird deaths. Oil? Coal? Natural Gas? the environment and ecosystem that supports the environment is completely ruined with long-lasting health impacts on both humans and animals. i love birds and am happy to read that at wind energy is trying to be in harmony with the environment. take a look at a mountain top in Appalachia that had the great misfortune of containing a coal deposit and inventory the wildlife there after an energy company worked its magic.

  6. Jack Simmons
    Denver, Colorado
    February 4, 2013, 6:48 am

    When will the double standard on threatened birds end? If an oil company was killing birds on the scale of this wind farm, we would never hear the end of it. The executives would be looking at jail time. But its ok for wind farms. We’re in the interesting position of killing birds to protect the environment.

  7. Bruce Miller
    February 3, 2013, 9:51 pm

    in America the homo sapien is threatened by lack of clean energy! kill a cat save many birds?

  8. mike
    February 3, 2013, 2:16 am

    I grew up in Southern California, and as a kid in the 70s, red tail hawks and many other large hawks (and maybe eagles, i was too young to know the difference) were very common and they range over large areas..the numbers are greatly reduced now, so a 50% reduction could just be from the reduced number of birds..that would make sense. I’m glad they are doing something about this though. A large red tail soaring on updrafts is pretty impressive and they are important in the food chain too.

  9. Sunshine100
    February 1, 2013, 12:50 pm

    In northern Virginia, the kestral is considered to be “threatened” as their numbers have decreased significantly. It may be the result of explosive suburbian development of previously wide open fields. Additionally, the Vultures have been chased out of the interstate I-495 beltway (they were the only remaining flock inside the beltway until their roosting site was destroyed to allow for housing construction), and serious harassment of the vultures continues as they self-relocate further south due to the NIMY effect. Lastly, the counties have declared full-scale destruction of trees in northern VA. One major change is that construction companies now wait until winter before destroying forests. The Board of Supervisors heard the large number of people’s complaint of summer tree destruction and made a change to the permit policy.