Four wind energy facilities in Wyoming — Campbell Hill, Top of the World, Silver Sage and Happy Jack — caused unintentional impacts to golden eagles for which the Department of Justice required compensatory mitigation. Duke Energy was tasked with implementing a comprehensive migratory bird compliance plan to avoid and minimize, to the maximum degree practicable, golden eagle and other avian mortalities associated with its wind projects.

Included in the company’s activities were the development of life-of-project bird and bat conservation strategies, informed curtailment, prey reduction, the study of eagle-turbine interactions associated with collision risk and rigorous monitoring of migratory bird mortalities occurring at its facilities. In addition to these monitoring and management requirements, Duke Energy provided $340,000 for the conservation of golden eagle habitat as part of its compensatory mitigation efforts.

The Conservation Solution

The Conservation Fund worked in collaboration with the U.S. Fish and Wildlife Service and The Nature Conservancy to identify a conservation project that could compensate for golden eagle mortality at two of these wind power sites in Wyoming. The mitigation funding provided by Duke Energy was matched by grant funding from the Knobloch Family Foundation and the Wyoming Wildlife and Natural Resources Trust to acquire a perpetual conservation easement on a privately owned 3,802-acre cattle ranch where 69 active golden eagle nests had been documented within a three-mile radius.

This ranch, situated along Muddy Creek in Carbon County, Wyoming, is part of the Little Snake River Conservation Priority Area, and is surrounded by approximately 75,000 acres of public grazing lands.

Outcome Highlights

Conservation

The conservation of this ranch yields many benefits beyond safeguarding one of the highest densities of nesting golden eagles in the United States. The mixed-grass prairie, riparian streams, sagebrush steppe, greasewood flat and limber pine that can be found on the property provide habitat for many other sensitive species — including ferruginous hawks, burrowing owls, greater sage-grouse and the flowering Gibbens’ beardtongue — and an important highway underpass on the ranch allows elk and mule deer to migrate safely each year. The water quality of the streams, protected by the natural functions of the habitat, benefits rare fish species such as the Colorado River cutthroat trout. There is also potential to protect and propagate high-quality habitat for other native fish, including the roundtail chub, speckled dace, bluehead sucker, flannelmouth sucker, and mountain sucker.

Economic

This project meets the obligations of the compensatory mitigation while maintaining the economic benefits of traditional agricultural production.