Developing a Model to Estimate Golden Eagle Take at Wind-Power Facilities

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Simple counts of carcasses found at wind farms do not reflect actual fatalities because some are removed by scavengers, or are overlooked by or fall within areas inaccessible to searchers. Because the density of carcasses generally declines with distance from the turbine, the location and configuration of inaccessible areas can greatly affect the proportion of carcasses that might be missed.

USGS researchers, who developed a method to model spatial distribution of carcasses beneath turbines, are starting a new study using data from white-tailed eagles in Norway as surrogates for U.S. bald and golden eagles that are not found in adequate numbers at any given facility to allow for reliable estimation of eagle-carcass density. Applicability of white-tailed eagle models will be tested using observations from several sites in California. Results will be used by the USFWS in determining take limits for new wind-power facilities and estimating actual eagle take post construction.