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Eagle expert warns of population collapse 

Credit:  East County Magazine | October 29, 2012 | eastcountymagazine.org ~~

Wildlife biologist Jim Wiegand, vice president of Save the Eagles International, has sent a letter to Bureau of Indian Affairs’ regional director  Amy Dutsche warning that the Tule Wind  project will be “deadly” for eagles in our region. 

Tule Wind proposes industrial-scale wind turbines turbines on federal, state, private and tribal (Ewiiaapaayp) lands.  Wiegand contends that eagle populations across the state are collapsing due primarily to collisions with wind turbines and that other studies have provided misleading information.

Below is his letter in full:

Friday, October 19, 2012

Amy Dutschke, Regional Director

Bureau of Indian Affairs

Pacific Regional Office

2800 Cottage Way

Sacramento, CA 95825


Dear Ms. Dutschke:                                                                                                                                                         

I have read the assessments about the impacts to golden eagle by this project. They are not factual and are very misleading. The mortality impacts from this project will lead to further population declines for this species.                                                                                                                                         

WRI [Wildlife Research Institute] provided misleading information about eagle mortality at wind projects

At the 580 MW Altamont Pass, studies have shown that wind turbines kill golden eagles at rate of  0.13 – 0.2 per MW per year (Smallwood and Thelander 2004 Chapter 3 Table 3-11.).   This equals 75-116 eagles being smashed out of the skies over Altamont each year.  Wind turbine strikes were also shown to be the number one cause of eagle mortality.

What the public does not understand is that Altamont Pass is not unique because at every wind farm located in eagle habitat, there are the same deadly combination of circumstances, wind currents, prey species, soaring eagles, and huge blades ripping through the air hundreds of feet up.  Eagles forage over hundreds and sometimes thousands of miles.  For this reason wind farms have a mortality footprint that far exceeds their boundaries.

In the Altamont pass region, Grainger Hunt during his seven-year study found that in the deaths of 100 radio-tagged eagles, wind turbine blade strikes killed at least 42. They were the number one cause of Golden Eagle mortality. He also added that the actual number was higher because the blades occasionally destroyed the transmitters.

I examined the golden eagle nesting records from the Grainger Hunt Surveys (2005) near Altamont Pass  and compared them to the current records of nesting golden eagles for area located in the Los Vaquerous Reservoir watershed north and northwest of Altamont pass. This land is now managed by the Contra Costa County Water District. The records show that there has been a golden eagle decline of at least 50% in nesting golden eagles since 2005. Where the there were once 8-9 nests, there are now only 4.

WRI has provided insufficient data about the status of the golden eagle in the region

In the eagle surveys around the Tule and Ocotillo this year there was only 1 nest that produced young in 2012. This is an area that represents over 1000-1200 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.”                                                                                                                                                             

I have read over a number of raptor surveys conducted recently in the Southern California region. One of the Mojave surveys was conducted by C2MHill in 2010.  They found 2 active (in the true sense) raven nests, 9 red-tailed hawk nests, 3 prairie falcon nests, and 2 great horned owl nests in an area of over 600 square miles.  But they also found 12 unoccupied golden eagle nests in area that they felt were at one time built by 3-4 nesting pairs.                                                                                                                                                         

In 2010 the Wildlife Research Institute conducted raptor surveys over a 1500 square mile area in the Mojave. They found 34 golden eagle nests and but only one that was occupied and productive.  The sum of these two surveys found 45 empty eagle nests and only 1 truly active eagle nest over a 2100 sq mile region of the Mojave.

In another 2010, 650 sq mile raptor survey ( Bloom Biological)  conducted north of Big Bear Lake,  8 more inactive eagle nests were found. From looking at the map of these locations the empty nests appear to represent at least 2 and possibly 4 more abandoned golden eagle territories.

In the WRI eagle surveys conducted for Tule wind project and Ocotillo wind projects a large numbers of empty nests were also found.   In the 2010 WRI stated ten historic golden eagle territories were surveyed, of which six were said to be active, but of those, only three of the eagle nests were actually occupied with incubating adults.  Again in 2011 WRI surveyed what they claimed to be eleven golden eagle territories, six were said to be occupied during the first round of surveys (Cane Brake, Coyote Mountains – West, Garnet Mountain, Glenn Cliff, Monument Peak, and Moreno Butte).  But in the most important statistical category as it relates to eagle populations, only three of the territories were confirmed as being productive (eggs or young) during the second round of surveys (Cane Brake, Glenn Cliff, Moreno Butte).

WRI provided a meaningless analysis of regional golden eagle occupancy

The WRI surveys do not accurately discuss the dozens of abandoned nests found or give reasons for the so called active eagle territories being non productive.  It is well known eagle do have alternative nest sites but in looking at the surveys it is apparent that there are large numbers of eagle territories not being occupied by adult pairs of eagles. This abandonment of territories is a clear sign of a population collapse on a large scale.                                                                                                          

Despite the confusing descriptions for given for eagle usage by researchers, this is very clear evidence of an alarming golden eagle population decline in Southern California.  The number of nesting eagles (by proper definition) is the core of the population and represents the single most important criterion for analyzing any golden eagle population.                                                            

When these surveys were conducted in2010 it was a wet year for the desert. If more adult eagles were present, they would have nested.  Also as the surveys pointed out, other raptor species had no problems nesting in this habitat.

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.

In any wind industry generated report, survey, or study pertaining to an assessment of golden eagle population numbers, unless an eagle nest is accounted for in the context I have stated, there are no credible conclusions that can be drawn. If a golden eagle happens to be seen at a location during a field survey, it does not necessarily mean it has a territory or that it has a mate, and should never be used to exaggerate a population estimate. A single eagle traveling around California (because they do travel hundreds of miles) could be seen in ten different locations in CA and from the reports I have reviewed, then could construed to represent ten eagle territories.                                                                                    

Maybe this is why WRI claims there are currently 355 golden eagle territories in the Mojave region.  If so they are primarily abandoned territories.

WRI has understated the impact that the project will have on the golden eagles

For decades wind industry generated mortality studies for wind projects have been inherently flawed. The procedures for conducting these studies make them totally unreliable.  Mortality studies look for birds in areas 8-10 times too small just around the turbines. However, there are many larger birds that when struck on the project site can actually travel off the site before the impacts fully set in.  Some of these individuals will end up hundreds of yards outside the project area before the effects of the collision kill them and they are therefore incorrectly omitted from the mortality study.  Others upon impact are hit and travel like a baseball far outside study areas. This is especially true for new generation wind turbines that reach 400 feet into the air.                                                                 

Most mortality studies have been conducted every 15 to 30 days, instead of every day, allowing significant time for scavengers to take most of these fallen birds away.  Further, these surveys are done by the human eye, rather than dogs which could quickly and more accurately detect fallen birds.  Finally, these studies do not include a count of the birds and bats that are permanently disabled or mortally wounded, which would show the true harm caused by these turbines.  Without accurate and adequate mortality studies, the true irreparable harm to avian species caused by wind  projects can never be fully identified or understood.

The true impact of wind turbines on Golden Eagles cannot be ignored.  Like many other raptors, Golden Eagles prefer windy areas because it makes soaring and gliding easier.  But wind energy developers are also looking for windy spots, and that puts wind turbines and raptors on a direct collision course.

The Tule ridge line project will be deadly for other reasons not discussed. Ridgeline projects are the most deadly. Diablo Winds and the unmentioned Buena Vista wind projects both located at Altamont, are ridgeline based projects. The Buena Vista project with the larger 1 MW turbines had an eagle kill rate of .143 per MW, nearly 3 times what was reported at Diablo Winds.  There is also something else that WRI did not disclose, paired up Golden Eagles is brushy areas (like the conditions in the Tule ridgeline habitat) frequently hunt in teams. One will fly low for the purpose of flushing prey, the other eagle flying higher in the sky and behind, will pick off prey that is fooled by mainly paying attention to the lower eagle. I have witnessed this ridgeline hunting behavior and it takes place primarily in the turbine sweep zone between 30 and 500 feet up.

Golden Eagles and other raptors often supplement their diet by scavenging.  Wounded or freshly killed birds (or other prey) found beneath huge wind turbines will always attract Golden Eagles.  One must also keep in mind that a soaring eagle is a somewhat relaxed eagle and any push or gust of wind could throw even a careful eagle into the path of a sweeping turbine blade before it can take one wing beat. These foraging and scavenging behaviors put the Golden Eagle in direct risk of collision with wind turbine blades                                                                                  


WRI has not addressed the cumulative impacts caused by this project.


The cumulative effects on the golden eagle from the wind industry can be seen in the severe population declines or territory abandonment I have shown to exist in Southern California.                                                                                                                     


Shawn Smallwood a researcher that that has probably spent more time than anyone studying the impacts of wind turbines on birds, had this to say in 2009 about the cumulative impacts to expect from wind energy in California as it tries to meet its 33% RPS (California’s Renewables Portfolio Standard ).. ” As explained in CARE’s comments on the Tehachapi Renewable Transmission Project EIR/EIS, the available evidence indicates that not only would wind energy generation require the development of up to 4,771 square miles to achieve the 33%(RPS)based on fatality rates from four wind resource areas in California, could cause annually fatalities of >23,000 burrowing owls, >22,000 American kestrels, nearly 9,000 red-tailed hawks, >1,500 golden eagles, nearly 64,000 raptors of all kinds, >370,000 birds of all kinds, and nearly 24,000 bats of all kinds, just by collisions alone (Fig. 1). We do not believe these fatality rates would be sustainable, and we believe the California public will not accept them.”                                                                                                                            

While I agree with Shawn Smallwood about the coming devastation to bird life from wind energy development in California, I do not believe that the wind industry mortality in California will ever reach his figures of 23,000 burrowing owls and 1500 golden eagle fatalities a year. Their populations will crash long before these numbers can be reached. As I have shown, it is already happening.

There are no contingency plans for the golden eagle if the population declines

Every nesting territory is important. I would estimate that the number of productive golden eagles nests in San Diego County is approximately 10.  I  believe  there are  NO active and productive golden eagle nests remaining in Imperial County. I also believe that by analyzing all the golden eagle surveys that have been conducted to date,  it is safe to assume that there are no more than 25 productive golden eagle nests left in the California Mojave region. This is a huge area that represents 20-25 percent of the state.  

As I have pointed out, mortality studies conducted by the wind industry are seriously flawed. Every cumulative impact study I have looked pertaining to the wind industry is unreliable because they have all been generated from the years of flawed data taken from biased and flawed mortality studies. Therefore how many eagles that are killed by these turbines will be nearly impossible to determine but certainly more than what has been presented.

In the Table 6-1 Summary of Advanced Conservation Practices, there really needs to be only one reasonable step in the conservation plan. That being, if the golden eagle population is reduced in the 1000-1200 square mile area of the Tule and Ocotillo wind project sites; there should be a complete curtailment of turbine operations.

In Southern California where there are many installed wind energy projects already located in eagle habitat that an eagle doesn’t have to fly far before it is in great danger.  This project will add one more deadly stop-over for the population. 

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.                                                                                                                                                     

For the many reasons I have given, new credible golden eagle surveys and assessments should be conducted before one more wind turbine is built in this eagle habitat.   

Respectively submitted,

Jim Wiegand, Independent Wildlife Biologist,

Vice President Save The Eagles International

4525 Yellowstone Drive

Redding, CA 96002

Source:  East County Magazine | October 29, 2012 | eastcountymagazine.org

This article is the work of the source indicated. Any opinions expressed in it are not necessarily those of National Wind Watch.

The copyright of this article resides with the author or publisher indicated. As part of its noncommercial educational effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations. Send requests to excerpt, general inquiries, and comments via e-mail.

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