The effects of wind turbines on birds have been studied for almost twenty years, mainly by visual observation and radar. This has provided a good insight in the collision risks for several land-based wind farms. Still more accurate data are needed to assess the actual mortality rates and eventually the collision risks, especially for large (offshore) wind farms.
A new method for detection and registration of bird collisions has been developed that is suitable for continuous remote operation in both onshore and offshore wind farms. A prototype has been tested successfully on a land-based multi-megawatt turbine.
Compared to other methods employed so far this registration system will reduce the uncertainty in the results of the number of birds killed by collisions with wind turbines. It runs continuously and makes identification of species possible. It has been investigated whether this system can also be used for monitoring of other events in order to save costs for inspection and repair after incidents. For offshore wind farms, the WT-Bird system is in fact the only alternative to count the number of bird collisions.
Functional tests with bird dummies of only 50 grams and 6.5 cm in diameter, representing the smallest abundant bird species along the Dutch coastal region, hitting the rotating blades showed that the majority of impacts were detected. The flight track of these dummies and the collision events were clearly visible on the video registrations. Also the operational experience from endurance tests is presented.