Bird migration

Measurements for bird migration research on the FINO3 research platform in the context of planned offshore wind energy use

Avitec Research GbR
Dipl.-Geogr. Reinhold Hill

It is aimed in the course of the project to obtain information on the space-time sequence of the flight movements of birds and on the variability of species-specific migration intensities on a daily and annual basis in the German section of the North Sea.

Illustration: the illustration shows a gull flying past. The addition of individual images of the camera over a period of 1 min facilitates the generation of a new image, which shows the bird flying past as a flight trace.

The measurements are carried out with comparable remote sensing methods as used on FINO1 at the same time in part since October 2003, so that the data from both offshore locations is directly comparable:

• Horizontal radar measurements with a parabolic antenna to determine migration intensities and directions. The use of parabolic instead of traditional bar antennae facilitates, by directly measuring back-scattering energy, the calculation of migration rates and excluding insects to the greatest possible extent.
• Use of a high-resolution video camera to make migrations visible.
• For a period of 1 min facilitates the generation of a new image which shows the passing bird's flight as a flight trace.
• The combined comparison of migration intensities determined using radar technology and camera technology of birds registered in the close proximity of the platform permits more extensive conclusions to be drawn regarding the possible attractive impact or avoidance behaviour of this artificial structure erected offshore on migratory birds.
• Use of a largely automated bird call registration to determine migration intensities and composition of species calling during the migration.
• Special software recognises the characteristics of bird calls compared with sea, wind and rain noises and records these digitally as files. These can then be evaluated by experienced ornithologists and specialised software.
• This facilitates detailed insights into the spectrum of bird species which call during migration. The method also makes it possible to determine when a particularly large number of birds stay within the vicinity of the lighted platform at night and are then particularly at risk of collision.
• Registering deaths: counting, species determination and assessment of the injury pattern of dead birds, found at visits to the platform.
• This method can put aspects of the existing risk of collision into concrete terms. Bird strike and fear of the impact on population trends of numerous bird species by the existing offshore WEA [=wind energy installation] plans and development of suitable avoidance and reduction strategies are central to the endeavours of the bird migration research being conducted here.

The data recording is to take place before the approved wind farms are built, so that a direct comparison can be made of the situation before, during and after construction of the offshore wind farms.