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.

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:

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

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.

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

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