Four turbines at the Smøla wind farm in Norway are to have one rotor blade painted black to see whether increasing the visual contrast of the turbine against its background might help to reduce bird strikes.

Energy company Statkraft, which operates the farm, says that several white-tailed eagles (also called sea eagles) are found dead on the ground having flown into turbines at the inland wind farm.

As well as testing black rotor blades, the INTACT project will also examine whether increasing the visibility of the turbine's towers might prevent strikes from birds that fly lower than eagles, such as ducks and grouse.

Additionally, some turbines are to be fitted with ultraviolet lamps. Unlike your eye, a bird's eye is sensitive to the ultraviolet part of the electromagnetic spectrum. Should UV lights prove effective, the intention is to go on to test UV-reflecting paint. Paint has an advantage over UV light in that it can be applied during the production of the turbine.

Smøla wind farm caused controversy within months of its opening in 2005 due to the immediate effect of the turbines on the local white-tailed eagle population. However, since that time, Statkraft claims that the wind farm has become a research hub to better understand the issue.

"Countless hours of research have been spent on this issue since the Smøla wind farm was completed in 2005, and there are few places in the world where so much is known about bird behaviour in the vicinity of wind power generation," says Bjørn Iuell, a biologist and environmental advisor at the company.

On average, the 68-turbine farm generates 356 GWh of electrical energy per year, which Statkraft says is sufficient to power 17,800 Norwegian households.

Energy Norway is "owner" of the project, and NVE, NINA, Statoil, Trønder Energi Kraft and Vattenfall are partners.