Guidance & Information Specific to Bird Interests
Assessing collision risks
The behaviour of birds in proximity to wind turbines is still not well understood though monitoring information on bird behaviour and collisions is gradually becoming available for some species.
For collision risk, SNH recommends an assessment of the number of collisions which would occur if birds take no avoiding action – this depends on levels of flight activity, the size and speed of the bird, and the dimensions and rotational speed of the turbine – followed by application of an avoidance factor to reflect that in practice, birds often succeed in avoiding a turbine blade, either by re-routing their flight, or by measured timing of their flight through the rotor, or by taking emergency avoidance action. The guidance below is for each of these stages:
- Windfarms & Birds: Calculating the theoretical collision risk assuming no avoidance action:
Guidance Note
Appendix 1 (excel spreadsheet)
