Wind Energy and Bats: Why Do They Kill Them?

by Margy Stewart

When I was a little girl, my big sister Sally brought home two orphaned baby bats. A pest-control officer had killed the adult bats at the tourist-mansion where she worked as a summer guide. Always a fierce protector of wildlife, Sally had tried to stop the extermination. In the resultant melee, she had rescued two tiny babies-each no bigger than a nickel.

I was Sally's willing sidekick in wildlife adventures, and I was thrilled to be recruited into a feeding regime. Every two hours, day and night, we held the babies on our hands, and using a doll's bottle, squeezed a drop of milk out in front of them. How thrilled we were when they crawled forward and lapped up the milk! How astonished we were when, minuscule as they were, they insisted on hanging upside down from the slightly elevated flap at the bottom of their box.

How was it that barely visible balls of fluff could express such batness?

Of course, we sisters were expressing pure naivete. We had no idea how to rehab orphaned animals. We were keeping the babies alive but we didn't know how to help them grow or thrive. After a month-when in the wild they would have been nearing full size--they were still tiny. When I opened their box one morning and found them stiff and dead, I cried and cried.

My sister flew into a rage. Why do they kill them? she screamed.

Now some sixty years later, as wind developers target more and more natural areas, wildlife advocates ask that same question: Why do they kill them?

When it comes to bats, extermination has too often been humans' go-to response.

Until the year 2000, intentional killing of bats by humans was the leading cause of Mass Mortality Events (MMEs), surpassing even the lethality of a fungal disease called White Nose Syndrome.

But today the leading cause of premature bat mortality is not intentional at all. Rather, what's pushing bat species toward extinction is an overlooked side-effect of industrial scale wind turbines. The U.S. Fish and Wildlife Service sounds the alarm about "large-scale fatalities of bats at wind energy facilties " and calls it "an unforeseen byproduct of wind energy development." The phenomenon is world-wide and no one doubts the seriousness of it. "Bats are dropping like flies" says Ball State University biologist Tim Carter. Ft. Hays State researcher Amanda Adams adds, "Bats are being killed in the millions by wind turbines."

The spinning blades that kill birds are not the culprit. What's killing bats is something called "barotrauma"-a sudden drop in air pressure near the blades that causes bats' lungs and blood vessels to explode. The taller the turbine, the bigger the drop in pressure-and the greater the number of deaths. "People call this green energy," says Carter. "I call it red energy."

These MMEs are particularly devastating because of bats' slow rate of reproduction. Adult bats produce only one or two babies a year, a low replacement rate normally compensated for by natural longevity. Bats can live as long as 30-40 years. Therefore, killing adult bats in their prime can quickly have a species-level effect.

Ever obsessed with ourselves, we humans are now realizing that bats provide us with "ecological services," especially by controlling pests. Bats save farmers an estimated $23 billion each year by preventing crop damage. An article this month in the Times of Israel talks about bats as the last hope for Israeli cotton farmers who are now facing pink boll worms that have developed resistance to pesticides and genetically modified cotton. But bats like pink boll worms. Bats are coming to the rescue!

But will humans come to the rescue of bats?

At first researchers wondered why bats couldn't stay away from turbines. Could the heat make the turbines seem like attractive roosting sites? But after several experiments, it's clear that bats are foraging near the turbines, following insects to their deaths. Could the lights on the turbines be drawing the insects which in turn draw the bats?

Through research partially financed by the American Wind Energy Association, methods have been devised to reduce lethality. When wind turbines are shut down on low-wind evenings and during periods of bat migration, bat mortality is reduced. A few wind facilities have implemented these measures, and some have also tried to compensate for killing bats by financing habitat preservation elsewhere. But those cases are the exception, not the rule.

In general, the issue of bats' lives has been ignored, by both wind companies and by elected officials. However, the reason is not lack of knowledge. Here in Kansas, seven species of bats were documented in Expedition Wind's project area in a study commissioned by Expedition Wind and submitted to the County Commission. Among the seven were three migratory species, especially at risk from wind turbines, and one federally-listed endangered species. The study summarized the risks to bats from wind turbines as well as measures to reduce mortality.

But "studies" do not have the force of law.

The Kansas Department of Wildlife, Parks, and Tourism also asks wind developers to provide bat protection plans. But agency "requests" do not have the force of law.

I have submitted a Freedom of Information Act request for any bat-protection plan submitted by a wind developer in Kansas.

To date I have not received a single one.