The problem of mass death of birds from a wind turbine could be resolved through painting one blade black. That makes it easier for birds to avoid a deadly encounter, say the findings published in Ecology and Evolution.
The recent study found that painting one of the four white blades on a wind turbine black significantly decreases the number of dead birds by 72 per cent.
In fact, wind farms would kill twice as many bats as they do birds, the figures would be: 111 – 333 birds per turbine per year, and 222 – 666 bats per turbine/year, according to Mark Duchamp, head of Save the Eagles International.
According to the researchers from the Norwegian Institute for Nature Research conducted a trial on the remote island of Smola comparing how many birds were killed by four painted turbine compared to their untouched neighbours.
During seven and half years, the researchers regularly scoured the bottom of the turbines with specially trained sniffer dogs to identify any bird carcasses. The difference between periods when one of the four blades was painted black was impressive.
For the eight turbines included in the research – four painted and four left bare – a total of 1,275 searches were conducted between 2006 and 2016.
A total of 82 carcasses were found and statistical analysis revealed the birds which benefit the most from the pained blades are raptors and large soaring birds.
This includes eagles and vultures, who have been high-profile casualties of wind turbines. No white-tailed eagle carcasses were recorded after painting the blades.
The study also found that while the number of dead birds dropped at painted turbines, it did not trigger a spike in the number of casualties at neighbouring turbine zones. As the scientists suggest, the reason painting a single blade works is due to a phenomenon called ‘motion smear’.
This means that, although birds often have exceptional eyesight, the rotating blades appear invisible. Birds have extremely high-resolution eyesight in their peripheral field of vision, and the front-facing eyesight is not as good.
Thus, within assumed open airspace, birds may therefore not always perceive obstructions ahead thereby enhancing the risk of collision, the study says.