As wind energy deployment increases and larger wind‐power plants are considered, bird fatalities through collision with moving turbine rotor blades are expected to increase. However, few (cost‐) effective deterrent or mitigation measures have so far been developed to reduce the risk of collision. Provision of “passive” visual cues may enhance the visibility of the rotor blades enabling birds to take evasive action in due time. Laboratory experiments have indicated that painting one of three rotor blades black minimizes motion smear (Hodos 2003, Minimization of motion smear: Reducing avian collisions with wind turbines). We tested the hypothesis that painting would increase the visibility of the blades, and that this would reduce fatality rates in situ, at the Smøla wind‐power plant in Norway, using a Before–After–Control–Impact approach employing fatality searches. The annual fatality rate was significantly reduced at the turbines with a painted blade by over 70%, relative to the neighboring control (i.e., unpainted) turbines. The treatment had the largest effect on reduction of raptor fatalities; no white‐tailed eagle carcasses were recorded after painting. Applying contrast painting to the rotor blades significantly reduced the collision risk for a range of birds. Painting the rotor blades at operational turbines was, however, resource demanding given that they had to be painted while in‐place. However, if implemented before construction, this cost will be minimized. It is recommended to repeat this experiment at other sites to ensure that the outcomes are generic at various settings.

Renewable energy production is regarded essential to meet the increasing energy demands while also reducing emissions of CO 2 necessary to reduce risk of global warming (IEA, 2016;IPCC, 2014). In recent years, the production of wind energy has increased worldwide and is still developing fast (IRENA, 2017).Although regarded as a low-carbon energy option, wind energy production may cause negative environmental effects, especially on wildlife (Tabassum-Abbasi, 2014). At onshore wind-power plants, birds and bats are particularly vulnerable, with effects ranging from mortality caused by collisions with turbines, to displacement/avoidance and habitat loss (

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