The project will contribute towards estimating possible risks for migrating birds to collide with offshore wind farms. In addition, models are to be developed to predict the risk that birds collide. These models are used to work out criteria which may possibly serve as a basis to minimise or even avoid impacts.
A large number of birds migrate across the German part of the Baltic and North Seas on the way from breeding areas to wintering areas and back. The majority of these birds, passerines above all, migrate during the night. In the German Exclusive Economic Zone (EEZ), collisions of birds with wind turbines are usually considered to be a major conflict between nature conservation and further development of offshore wind farms. So far, only little information is available on temporal and spatial migration patterns in the offshore area. It also remains unclear to what extent migrating birds collide with offshore wind turbines.
The following specific aims are pursued in the project:
- To describe bird migration in the German EEZ of the North and Baltic Seas with a particular focus on spatial and temporal variation and existing gradients (e.g. distance from coast).
- To model intensity of bird migration and flight heights depending on the prevailing weather conditions.
- To develop a prediction model of bird migration in the rotor area based on weather parameters.
- To estimate the cumulative risk for birds to collide with offshore wind turbines.
- To work out criteria that may serve as a basis to develop and initiate measures to reduce or even avoid bird collisions.
The study is based on radar surveys of bird migration as well as flight calls recorded at night. These data originate from accompanying surveys of wind farm projects in the North and Baltic Seas over the last ten years and were collected in ship-based surveys and on offshore platforms. Weather data are evaluated additionally.
Analysis of bird flight calls: first results
In this substudy, flight calls of selected species recorded between 2008 and 2015 in 13 wind farms were included. Many bird species have specific flight calls. The number of calls is not necessarily proportional to the number of birds. Even so, evaluation of flight calls is the only available method to obtain information on nocturnal flight activity of single species.
Among other things, first results reveal that bird migration highly depends on weather conditions. High call activities of migrating birds were not only recorded under favourable migration conditions (e.g. tail winds), but also in adverse weather conditions (e.g. rain, poor visibility). Under these conditions, the collision risk for migrating birds will probably be higher.
For further information please refer to the following documents:
Welcker, J. & Vilela, R.
Analysis of bird flight calls from the German North and Baltic Seas - Report from the ProBIRD project
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The project is carried out on behalf of the Federal Maritime and Hydrographic Agency (BSH), funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU).
Project duration: until end of 2019
Funding ID: FKZ UM15 86 2000