Improving fatality estimates at wind energy facilities
The density-weighted proportion--or dwp--R software package improves estimates of total bird and bat fatalities at wind energy facilities by accounting for the fraction of carcasses that fall outside the searched area.
Why was the dwp software package developed?
Searching for animal carcasses around wind turbines can provide valuable information on the impact of renewable energy development on wildlife populations. However, searching the entire area in which a bird or bat could fall after being struck by a turbine is not feasible. Searches can be limited by rough terrain, access restrictions, or limited time and resources. Since wind turbines are necessarily located in places with high winds, carcasses can also be blown far from turbines after they are struck. Not accounting for carcasses outside the searched area results in inaccurate mortality estimates, which can hamper efforts to study and mitigate for wildlife mortality.
What does it do?
The dwp R software package estimates the fraction--and associated uncertainty-- of the total number of carcasses lying within searched areas around wind turbines. The dwp software output is designed to be compatible with the Generalized Mortality Estimator--or GenEst--software package (Dalthorp et al. 2018). Together, they can provide an accurate estimate of total mortality.
How does it work?
To get started, the user uploads the layout of the searched area and adds the locations of carcasses. The software fits a wide array of possible carcass-density models that reflect how the density of carcasses changes with increasing distance from the turbine. Using evaluation criteria provided by the software, the user selects the best model to estimate the fraction of carcasses expected to lie within the searched area. This dwp estimate and associated uncertainty contribute to the estimate of total mortality generated by GenEst.
Whom is it for?
The software package requires a basic familiarity with R. Users that could benefit from this software include staff from natural resource agencies and energy companies tasked with assessing wildlife mortalities at wind energy facilities, researchers studying impacts of wind turbines on wildlife, or people developing mortality mitigation strategies.
Management implications
- The dwp software package provides an accurate estimate of the fraction of carcasses expected to land within the searched area around wind turbines.
- The estimate generated by dwp contributes to the estimate of total mortality at a wind energy site.
As wind energy production expands across the country, better mortality estimates at individual sites will result in a better understanding of wildlife impacts and inform regulatory decisions.
This brief refers to:
Dalthorp, D., Huso, M., Dalthorp, M., and Mintz, J., 2024, Accounting for the fraction of carcasses outside the searched area in the estimation of bird and bat fatalities at wind energy facilities: U.S. Geological Survey Techniques and Methods, book 7, chap. A3, 104 p., https://doi.org/10.3133/tm7A3.
Dalthorp, D., Madsen, L., Huso, M., Rabie, P., Wolpert, R., Studyvin, J., Simonis, J., and Mintz, J., 2018, GenEst statistical models—A generalized estimator of mortality: U.S. Geological Survey Techniques and Methods, book 7, chap. A2, 13 p., https://doi.org/10.3133/tm7A2.
The density-weighted proportion--or dwp--R software package improves estimates of total bird and bat fatalities at wind energy facilities by accounting for the fraction of carcasses that fall outside the searched area.
Why was the dwp software package developed?
Searching for animal carcasses around wind turbines can provide valuable information on the impact of renewable energy development on wildlife populations. However, searching the entire area in which a bird or bat could fall after being struck by a turbine is not feasible. Searches can be limited by rough terrain, access restrictions, or limited time and resources. Since wind turbines are necessarily located in places with high winds, carcasses can also be blown far from turbines after they are struck. Not accounting for carcasses outside the searched area results in inaccurate mortality estimates, which can hamper efforts to study and mitigate for wildlife mortality.
What does it do?
The dwp R software package estimates the fraction--and associated uncertainty-- of the total number of carcasses lying within searched areas around wind turbines. The dwp software output is designed to be compatible with the Generalized Mortality Estimator--or GenEst--software package (Dalthorp et al. 2018). Together, they can provide an accurate estimate of total mortality.
How does it work?
To get started, the user uploads the layout of the searched area and adds the locations of carcasses. The software fits a wide array of possible carcass-density models that reflect how the density of carcasses changes with increasing distance from the turbine. Using evaluation criteria provided by the software, the user selects the best model to estimate the fraction of carcasses expected to lie within the searched area. This dwp estimate and associated uncertainty contribute to the estimate of total mortality generated by GenEst.
Whom is it for?
The software package requires a basic familiarity with R. Users that could benefit from this software include staff from natural resource agencies and energy companies tasked with assessing wildlife mortalities at wind energy facilities, researchers studying impacts of wind turbines on wildlife, or people developing mortality mitigation strategies.
Management implications
- The dwp software package provides an accurate estimate of the fraction of carcasses expected to land within the searched area around wind turbines.
- The estimate generated by dwp contributes to the estimate of total mortality at a wind energy site.
As wind energy production expands across the country, better mortality estimates at individual sites will result in a better understanding of wildlife impacts and inform regulatory decisions.
This brief refers to:
Dalthorp, D., Huso, M., Dalthorp, M., and Mintz, J., 2024, Accounting for the fraction of carcasses outside the searched area in the estimation of bird and bat fatalities at wind energy facilities: U.S. Geological Survey Techniques and Methods, book 7, chap. A3, 104 p., https://doi.org/10.3133/tm7A3.
Dalthorp, D., Madsen, L., Huso, M., Rabie, P., Wolpert, R., Studyvin, J., Simonis, J., and Mintz, J., 2018, GenEst statistical models—A generalized estimator of mortality: U.S. Geological Survey Techniques and Methods, book 7, chap. A2, 13 p., https://doi.org/10.3133/tm7A2.