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.
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.