Abstract
The incidental take of golden eagles (Aquila chrysaetos) as a result of wind energy development requiressome form of compensatory mitigation. Although several options have been proposed, only one has been formerlyaccepted and implemented, and the lack of options can limit the permit process for wind facilities. We developed a modelto estimate numbers of golden eagles that die when struck by vehicles when eagles scavenge road kill to evaluate removalof road-killed carcasses as an additional mitigation option. Our model estimates vehicle collision rates as a function ofeagle densities, road traffic volume, and animal carcass abundance at the scale of a Wyoming, USA, county during fall-winter, and quantifies the effects of different mitigation strategies, including estimates of uncertainty. We evaluated theplausibility of our model estimates by predicting mortality rates for each county in Wyoming and comparing overall statemortality to current estimates of mortality using derived estimates from expert judgment. We also developed a context-dependent analysis of potential mitigation credits controlling for carcass number, traffic volume, and background carcassremovals. We found that mitigation credit should be highest in areas with greatest number of carcasses. Collisionmitigation is a potentially useful addition to the mitigation toolbox for wind energy development or other activities thatneed to offset predicted golden eagle mortality and satisfy incidental take permit requirements.