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Expert: San Diego Wind Farm May Devastate Eagle Population

A turbine at Altamont Pass in Northern California | Photo: Bonita de Boer/Flickr/Creative Commons License

A California eagle biologist says that a wind power project in eastern San Diego County may pose a serious threat to golden eagles in the Anza Borrego region. The Tule Wind Power Project, approved earlier this year by San Diego County's Board of Supervisors, would place close to 100 turbines on 750 acres in the McCain Valley north of Boulevard.

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In comments on Tule Wind's avian and bat protection plan, submitted October 19 to the Bureau of Indian Affairs (BIA), biologist Jim Wiegand -- Vice President of the wildlife protection group Save the Eagles International -- charged that the project will kill or injure more golden eagles than its formal planning documents suggest, and that the species is already on the verge of extirpation in Eastern San Diego County.

The BIA is involved in approving the project as the turbines would occupy Ewiiaapaayp tribal land, as well as some privately owned land, and public lands managed by the state and federal governments.

In his comments, which were reprinted in the East County Magazine, Wiegand charges that the Wildlife Research Institute, which provided biological consulting services to the Tule Wind's builder Iberdrola Renewables, wrongly assumed eagle nests to be indicative of the number of breeding pairs of eagles in the area.

In the eagle surveys around the Tule and Ocotillo this year there was only one nest that produced young in 2012. This is an area that represents over 1,000-1,200 square miles of eagle habitat or territories. San Diego County only has 4,525 square miles. Yet the media is putting out inaccurate numbers that give the appearances of there being 44-48 so called "active nests" or "nesting territories."

Wiegand says he estimates the actual number of productive eagle nests in all of San Diego County at about 10, with none remaining in Imperial County to the east. He adds that things aren't much better elsewhere in Southern California, in his view due to the proliferation of wind energy projects throughout the mountain passes of California:

Wind energy has been a disaster for the golden eagle. The negative footprint from wind energy projects has created ecological sinks for migrating and regional bird populations. The decades of killing of so many golden eagles by the wind industry is having a profound negative impact. The proof lies in Southern CA where there is evidence of a golden eagle population decline of 80-90 percent.

What's behind the alleged overestimates of eagle numbers? Wiegand says it's flaws in the surveyors' methodology.

In the last 10-15 years I have noticed a disturbing trend. Wind industry biologists have began using the words "territories," "active territories," "inactive nests," "nest territories" and "active nests" in their surveys and reports. These terms are vague, have different meanings, are misleading, and contribute to misrepresentations in population estimates. The term "active nest" when pertaining to the analysis of any nesting golden eagle population, should be used only if the nest is shown to be occupied by the presence of adult eagles, with eggs and/or dependent young in a given breeding season. A nest is not really active if it is used as a feeding platform and has newly added nesting material. These signs of use have nothing to do with an accurate analysis of the golden eagle population because abandoned eagle nests can be and frequently are used by a variety of species. Many eagle nests are used by ravens, hawks, owls, prairie falcons and even wood rats. The use of the eagle nests by these species makes the nests "active" but it has nothing to do with nesting golden eagles.

The total size of the Tule Wind project is yet to be worked out, but Iberdrola projects an eventual capacity of 200 megawatts. Wind turbines in the Bay Area's Altamont Pass cause an annual mortality of around 60 eagles. That's between .13 and .2 eagles per megawatt of capacity, says Wiegand. If, as he suggests, developers can expect a similar mortality rate at Tule Wind, the full project could kill a potential 25-40 eagles per year, which could quickly wipe out all golden eagles in the area.

Tule Wind isn't alone in the area: a few miles to the east, Pattern Energy's Ocotillo Express Wind Facility, now under construction, will place 112 wind turbines on 448-foot towers along the southeastern edge of Anza-Borrego Desert State Park.

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I have often heard that modern turbines have much lower bird kill rates due to more slowly turning blades, which birds can more easily see and avoid. This is relevant because Wiegand's analysis uses the bird-kill rates of older, smaller, faster-turning turbines in Altamont Pass as the basis for his estimates. Wiegand's article notes his some interesting reasons for his belief that bird-kill studies of modern turbines are flawed, but they are at this point assertions based on assumptions to contradict widely accepted studies.

Beyond that, trying to take a statistic like "Kills per megawatt" and apply them to a part of the state with a vastly different ecology, and a different density of eagles, seems mathematically unsound. As a basic sanity check, given that the "kills per megawatt" statistic does not account for the population density, his basic calculation would assume eagles would continue to be killed after they are extirpated!

Indeed, with half as many eagles, there should be half as many killed by wind turbines. Thus his conclusion that there are far fewer eagles in the area than estimated, while raising the importance of preserving those remaining, should proportionally decrease the estimate of the number that would be killed.


Aside from the wind farms dating from the 1980s in California which were developed at a time when siting practices were in their infancy and the knowledge of eagle and turbine interaction was poorly understood, wind energy is responsible for less than 2% of all documented eagle fatalities nationally.

The U.S. wind energy industry has demonstrated a willingness to work with the U.S. Fish & Wildlife Service to address higher than anticipated eagle fatalities. This includes the oldest facilities that have had historically the highest mortality rates, which are currently being “repowered” with new, larger turbines that have lower rpm and are spaced much farther apart. Eagle experts who have worked closest to the issue for decades predict that fatalities will drop by as much as 80% when repowering is completed. The wind energy industry is also working actively to avoid and reduce impacts at newly sited facilities.

The golden eagle population, both in California and nationally, is not well defined. As a result, while some data indicates that populations, in some areas, are unusually low, this is inconclusive. Further, it is unclear what the cause of this decline is, but most scientists agree that the cause is most likely persistent drought conditions throughout the southwest that affect the availability of both drinking water and prey that can support a robust eagle population.

Finally, the terminology of concern here is what all eagle biologists use, including theFish & Wildlife Service, and how developers have been directed by the Service to characterize site use by eagles.

For more information on wind energy and wildlife, see

John Anderson, Director of Siting Policy, American Wind Energy Association


Both the previous commenters are (intentionally?) ignoring the devastating impacts that LADWP has caused on eagle populations with it's absolutely cutting-edge "new" technology at "Pine Tree Wind Farm" - higher kill rates on a per-turbine basis than Altamont.

It is completely untrue that the avian deaths (let's not ignore other raptors and bats, both of which are critical for reducing disease vectors) have been "solved" by bigger turbines, when the evidence is that bigger spans mean bigger death tolls, not surprisingly.

Stop the greenwashing - we don't need to kill off our wilderness just to profit Big Energy while our built environment bakes, sprawls and wastes power. Energy efficiency, passive heating/cooling and rooftop solar should be the first, second and third targets of any renewable energy policy, then we can assess and see if storage, load balancing, additional generation, or otherwise is the best next step.

Killing Wilderness First is a seriously bad policy, especially since Big Wind produces low-quality power, and not much of that (see Nevada, where only 1 of their Big Wind installations can even scrape the bottom side of 10% capacity factor).


Here is a quick analysis of "The wind industry mortality scam."

A few days ago ABC Birds proclaimed this wind project to be the deadliest in North America

"Based on the 2011 data, Criterion estimates that if the project did not take steps to reduce the number of bats killed, it would result in between 13,238 and 26,477 bat deaths and approximately 8,960 bird fatalities during the expected 20-year operational life of the project. Each bird death is a distinct violation of the MBTA, a strict liability statute that prohibits the killing of birds even when the killing is unintentional."

I have read enough wind industry studies to realize that this industry and their so called hired experts, routinely manipulate studies for a desired outcome. Because of their production of bogus studies, the reported death toll to birds and bats from wind turbines, is actually far greater than what is being reported to the public. Here is a perfect example of one of these studies. At the Criterion Wind Project in Maryland, Post-Construction mortality monitoring studies were conducted.

Here is a description of Methodology used from the study............ "The monitoring study period was from April 5 to November 15, 2011. Search plots were established around all 28 turbines in the project and the carcass search schedule was for daily searches at all turbines (weather and safety permitting). Search plot size varied in shape and size, due to habitat constraints, but in most cases areas up to approximately 40-50 m (~130-165 ft) from the turbines were cleared of vegetation for access and construction purposes and this area was used as the search plot. Parallel transects were spaced and delineated approximately 5 m (~16 ft) apart within the search plot and surveyors systematically walked the transects while scanning the ground for fatalities or injured birds or bats."

All this looks impressive but it is nothing but a snow job. The cleared search plots were only the size of search plots originally used on the small turbines at Altamont which averaged 50 meters from the turbines. By comparison a 65kw turbine has a rotor sweep 38-40 times smaller with much slower blade tip speeds. The slower blade tips also result in reduced body impact distances. The small turbines with 22 ft blades reach about 80 feet into the air. By comparison the Liberty 2.5 MW Wind Turbines installed at the Criterion project are 400 or more feet tall and have 150 ft blades that reach out further than the mortality search plots. A proper search area of 200 meters out from each turbine, checked daily with trained dogs, would have found many times more fatalities. The industry also knows that larger birds like the golden eagle do not die immediately can travel hundreds or thousands of meters. Others upon impact travel like a baseball far outside study areas. This is especially true for these new generation wind turbines that reach 400 -500 feet into the air. Based on the flawed methodology used, the true death rate is far greater and likely to be at least 3-4 times what was reported.

Similar meaningless studies like this have been conducted all across America. They were used so the wind industry could proclaim to the world that their new behemoth turbines were safer. No one should ever believe it. These turbines huge turbines have greater tip speeds (approx 200mph) and rotate with lower winds.


Across the world people are finally waking up to the decades of deceit and the horrific impacts caused by the wind industry.

All this would have happened much sooner if conservation groups like the Sierra Club did not sell-out their causes. As it is, these groups end up in the mitigation process and get paid off for ridiculous solutions that do not work. So in the end these hypocrites get loads of money while claiming to protect the environment and the millions of birds being killed from wind turbines.

Today, thanks to wind industry mitigation, we now have California condors that will forever be trapped in small regions near their feeding stations and the highly endangered whooping crane population is rapidly declining. Sadly this migrating population is on its last legs because they will not be able to coexist with the thousands of wind turbines being installed along their migration route.

For decades prior to 2006 or before the wind industry invasion, whooping crane numbers had increased about 4 percent per year. But since 2006 the average mortality for this period has been about 41 cranes or close to 20 percent per year. Most importantly has been NO NET GAIN in this highly endangered species.

The propeller style wind turbine is also a prolific killer of eagles. The impact caused by decades of killing these raptors at wind farms can now be seen in an 80-90 percent population decline for the golden eagle in Southern CA. Thousands of miles surveyed only found 1 occupied nest and 45 empty nests. True to form, the industry will blame drought or climate change and create bogus studies to show this.

But not a negative word can be heard from any of these groups except the American Bird Conservancy. All this seems incredible since wind farms are a nothing but death traps to birds, much like the La Brea Tar Pits were to prehistoric animals.