Abstract
The Altamont Pass is both a significant wind resource area and important raptor-use area. Raptor flight patterns and burrowing owl burrow locations have been associated with fatalities caused by wind turbines, indicating wind turbine siting can influence collision rates. This study sought to develop maps of areas within the Altamont Pass where wind turbine operations might be safer for burrowing owls principally, and other raptors secondarily, and which could be used to guide the relocation of existing wind turbines to safer locations and to guide the siting of wind turbines installed in repowering projects. The positions of sampled raptor flights and burrows of burrowing owl, ground squirrel, and pocket gopher were related to a 10-meter digital elevation model of the study area. Two models were developed that successfully predicted burrowing owl suitable locations when validated by on the ground surveys. On average, burrowing owl burrows were lower on the slope than ground squirrel burrows, and they were on smaller and shallower slopes. Maps of likely burrowing owl burrow locations were produced, and wind turbines operating on the predicted locations of burrowing owl burrows also associated with greater mortality of burrowing owls and some other raptor species. Moving wind turbines away from these likely burrowing owl burrow locations should help reduce burrowing owl mortality in the Altamont Pass Wind Resource Area.