Scientists from the University of Amsterdam spent six years studying bird migration up to a kilometre above the Netherlands. They used weather radars from the Royal Netherlands Meteorological Institute (KNMI) and the ARTIS bird radar.
Bird migration peaks twice a year. Millions of birds then fly over the Netherlands between their breeding grounds in the Netherlands, northern and eastern Europe and their wintering grounds in Africa, southern Europe and the United Kingdom. Some birds migrate in large groups during the day, but most birds migrate at night, with a “carpet” of individual birds or small groups spreading across the Netherlands.
The majority of bird migration, depending on the conditions, 39-79% of birds, takes place at an altitude of less than 200 meters. Scientists report that this occurs at the top of wind turbines, due to the rotor area. The exact altitude depends largely on the weather, especially the wind. Birds fly up when there is a tailwind, and down when there is a headwind.
It is clear that more birds fly over certain areas than others. Scientists recommend taking this into account when looking for suitable locations for wind turbines. Bird migration maps can also help you take precautions when actually installing wind turbines. For example, wind turbines can be turned off at night when birds are migrating.
In this study only migratory bird movements were examined. To complete the bird maps, local movements of breeding and migratory birds should also be incorporated.
