Coexistence between migratory birds and wind energy production: The Gotthard wind park (Switzerland) as a case study

The global demand for wind energy is increasing, making it crucial to evaluate its impact on wildlife, particularly birds. Bird collisions can lead to significant fatalities, raising important questions about the effectiveness of wind power. This study focuses on one of the highest wind farms in the Alps, the Gotthard wind park (GWP), which features five turbines. The GWP's position along a migratory route mainly frequented by nocturnal migratory passerines has led to the implementation of radar systems for movement monitoring. Over a 4-year research period (from 2021 to 2024, covering 6 migration seasons) the purpose of the study was to analyze the GWP's collision rate and determine specific shutdown thresholds for each turbine to minimize collisions and prevent unwarranted turbine shutdowns. While the hours of blade shutdown differed markedly between the first (2021-2022) and second two-year (2023-2024) periods, this did not alter the number of collisions. A comprehensive strategy for managing GWP and optimizing energy production from individual turbines has been developed. This includes efforts to limit the impact on migrating bird populations to ensure it remains within acceptable ranges and to improve the efficiency of energy generation. The accomplishment was due to a detailed search of the carcasses on the ground, the presence of radar and visibility probes that allow for the identification of the most hazardous passages of passerine birds and the authorities' tolerance in developing an efficient GWP management system.