The available evidence suggests that wind farms can harm birds in three possible ways – disturbance, habitat loss or damage (both direct or indirect), and collision. Poorly sited wind farms have caused some major bird casualties, particularly in Tarifa and Navarra in Spain, and the Altamont Pass in California. At these sites, planners failed to consider adequately the likely impact of putting hundreds, or even thousands, of turbines in areas that are important for birds of prey. Tragically, killing many hundreds of birds as a result.
If wind farms are located away from major migration routes and important feeding, breeding and roosting areas of those bird species known or suspected to be at risk, there is a strong possibility that they will have minimal impact on wildlife.

The environmental impact of wind farms needs to be monitored and analysed as they operate – and policies and practices will need to adapt as we learn more about the impacts of wind farms on birds closer to home. We scrutinise hundreds of wind farm applications every year to determine their likely wildlife impacts, and object to about 7%, because they threaten bird populations.