The over-exaggeration of the “bird genocide” caused by wind turbine blades has been going on for decades, turning countless people away from that form of renewable energy. At one point it was even spread by the U.S. President himself who said that wind turbines caused cancer and lowered real estate value by 75%.
The latter two statements were proven to be even more wrong than the one about bird deaths. Not only is there no link between wind turbines and cancer but the “75% lower real estate value” statement was shown to be greatly exaggerated as well.
As far as the birds are concerned, however, it’s undeniable that wind turbines do cause a certain number of bird deaths. Anyone who’s ever walked around a working wind turbine has seen dead birds around it. However, every bit of statistics we could find on the matter shows that these bird deaths are much fewer than some make them out to be.
According to the U.S. Fish & Wildlife Service land wind turbines in the U.S. cause ~200,000 bird deaths per year. At the same time, however, bird collisions with simple building glass windows contribute to ~600 million bird deaths each year and cats kill a whopping 2.4 billion birds annually. This means that while 200,000 bird deaths are still unfortunate, wind turbines aren’t exactly the genocidal doom machines some people make them out to be.
Of course, the reason for this exaggerated myth’s existence is clear even if we overlook the fuel industry’s monetary interests in spreading it – the bird deaths from land wind turbines are just easily noticeable cause they all happen at the same places – they literally (and gruesomely) pile on the ground underneath the turbines.
There is good news, however. It turns out that there is a solution for lowering even those already low bird death numbers!
A study found that painting just one blade of a wind turbine black reduces bird deaths by 72%
The study took place in Norway’s Smøla wind farm for 11 straight years. The study was conducted by scientists from the Norwegian Institute for Nature Research and the results were published in the Ecology and Evolution journal.
The study worked with 8 land wind turbines on the island wind farm and was very simple in its premise – the scientists painted a single blade (out of three) on four of the eight turbines black and left the other four turbines untouched. The scientists had meticulously examined the bird death rate at the island for seven and a half years before the paint job and for three and a half years after it. During those 11 years, they conducted a total of 1,275 searches with dogs under the turbines in order to count every single bird’s death.
In that period, the scientists found a total of 82 carcasses, most of them of raptors and large soaring birds. These included eagles and vultures, as well as kestrels, and golden and snipe plovers.
Of all those deaths, however, only 24 occurred in the latter 3.5 years compared to 58 during the first 7.5 years. And more crucially – only 6 of those 24 deaths were under the four turbines with one painted blade on each and the other 18 – on the unpainted four turbines.
This makes for a 71.9% reduction of bird deaths with that one simple change.
The reason why this trick works is simple – the “motion smear” effect. While most birds have exceptional eye sights, the fast-moving wind turbine blades can appear near-invisible to them and they can’t notice them in time. Presumably, they are able to notice them eventually as flocks of birds can sometimes be seen flying away from wind turbines at the last possible second, but more often than not they’re not able to turn fast enough mid-flight.
By painting one of the three turbine blades black, however, the “motion smear” effect is created. This makes the rotating blades much more visible to birds from afar and they have more time to circle around the turbines rather than fly through them.
So, let’s return to the U.S. wind turbine bird death statistics for a second. If this simple solution is applied to all U.S. land wind turbines, the bird deaths can be lowered from the already low ~200,000 number to as little as ~56,000 annually.