A study of the Tahkoluoto offshore wind farm in Finland suggests that bird flight behaviour may adapt over time in the presence of offshore wind turbines. The research, Finland’s first bird radar-based study on offshore wind, was carried out through collaboration between Suomen Hyötytuuli and One Planet. It analysed bird movement patterns before and after turbine construction and is based on data collected between 2017 and 2021, covering around 2.83 million recorded flights.
Bird radar monitoring at the site was conducted between 2017 and 2023. The study examined changes in flight volumes and routes in the vicinity of the turbines and compared behaviour before construction with conditions during the first four years of operation.
Findings indicate that birds appear to adjust flight paths to avoid turbines, particularly at rotor sweep height where flight volumes declined after construction. At lower altitudes, birds continued to pass through the wind farm area but with small route adjustments to avoid turbines at close range.
The study also suggests that birds do not broadly abandon the area and instead learn to navigate around individual turbines. Observed impacts were reported to be lower than some theoretical predictions, with no signs of population-level effects on local breeding bird communities.
The project was funded by Ålandsbanken Baltic Sea Project.
