Abstract
This article presents some preliminary results from a study on the impact of three wind farms in Flanders (Belgium) on birds. The collision numbers varied from 0 to 125 birds per wind turbine per year. In 2002, the mean numbers for each windfarm were 24, 35 and 18 birds per wind turbine per year. It is important to note that the numbers of victims given must be regarded as an absolute minimum. The number of collisions at the three study sites seems to depend on the number of passing birds, and to a lesser degree on the size of the wind turbine. Most of the victims were locally common birds like gulls, ducks and pigeons but we also found rarer species such as Grey Heron, Peregrine Falcon, Redshank, Common Tern, Little Tern and Stonechat. The chance of a passing bird colliding with a rotor blade was calculated at between 1 in 12000 and 1 in 600. Most resting or foraging waterbird species kept a distance of 150-300 m from the wind turbines. At one location in the port of Zeebrugge we saw that most gulls and terns, flying between the breeding colonies and feeding areas at sea, crossed the line of wind turbines without mishap. Therefore, in contrast to the situation with birds engaged in seasonal and local migrations, during the breeding season, the wind turbine line posed no problem to these birds. However, this study demonstrates that in areas with many local migrations, there can be relatively high numbers of collisions. The impact on seasonally migrating birds is still unclear, and more research is urgently needed concerning the risk of collision.