Incidental eagle carcass detection can contribute to fatality estimation at operating wind energy facilities

Area of Science:

• Ornithology
• Wildlife Management
• Renewable Energy Impacts

Background:

• Bird collisions with wind turbines pose a significant threat to protected species like bald and golden eagles in the U.S.
• Wind energy facilities must document eagle take permit compliance through rigorous fatality monitoring.
• Operations and Maintenance (O&M) staff may offer a valuable resource for incidental carcass detection.

Purpose of the Study:

• To quantify the incidental detection of eagle carcasses by O&M staff.
• To estimate the overall probability of incidental detection (incidental g) for permit compliance.
• To identify key drivers influencing incidental detection rates.

Main Methods:

• Utilized feathered decoys as eagle carcass surrogates in monthly detection trials across 6 U.S. study sites.
• Employed logit regression models to analyze drivers like season, viewshed complexity, and carcass density.
• Applied an Evidence of Absence-based approach to estimate overall incidental detection probability, incorporating carcass persistence and area adjustments.

Main Results:

• Incidental detection probabilities for O&M staff ranged from 0.28 to 0.78 (mean = 0.48).
• Detection rates decreased with increased viewshed complexity and greater distance from the turbine.
• The overall probability of incidental detection (incidental g) ranged from 0.07 to 0.47 (mean = 0.31).

Conclusions:

• O&M staff demonstrated effectiveness in incidentally detecting eagle carcasses.
• Incorporating incidental detection enhances the reliability of estimating direct impacts on eagles.
• This approach offers a viable method for improving eagle fatality monitoring and demonstrating permit compliance.