Credit: Lyle Muller/IowaWatch file photo

The Iowa wind energy industry faces a bizarre problem. It is killing bats, and the demise sometimes comes in a gruesome way.

A lone wind turbine stands at Kirkwood Community College in Cedar Rapids. Students in Kirkwood’s Energy Production and Distribution Technologies program use the 417-foot tall, $5.2 million turbine as a learning laboratory. Photo taken June 28, 2015.
A lone wind turbine stands at Kirkwood Community College in Cedar Rapids. Students in Kirkwood’s Energy Production and Distribution Technologies program use the 417-foot tall, $5.2 million turbine as a learning laboratory. Photo taken June 28, 2015. Credit: Lyle Muller/IowaWatch

Wind turbine blades catch the little creatures in a vortex wake that ruptures their lungs, causing them to drown in their blood, experts have found. Many also die colliding with the turbines.

Which is more deadly? The scientific consensus on that still is unsettled.

Whatever the reason, the Iowa wind industry, an increasingly important segment of the economy, will have to deal with the deaths and a U.S. Fish and Wildlife Service effort to stop the slaughter of one species – the northern long-eared bat.

This is true even though the federal service acknowledges that wind turbines are not primary culprits in the demise of the northern long-eared bat because rules for protecting endangered species do not focus on one particular cause of death.

A schedule the service is working with has it making final decisions on the northern long-eared bat by year’s end.

Iowans have a big stake economically in all of this – not just for a robust wind industry but also for the survival of bats. Bats are good for medical research. They gorge on mosquitoes and save agriculture millions of dollars in insect crop damage and repellant expenses.


Experts’ death-toll estimates range from four to 18 bats per turbine annually, which equals 14,000 to 62,000 killings in Iowa.

Northern Long-eared bat.
Northern long-eared bat. Credit: Pete Pattavina/U.S. Fish and Wildlife Service

But the number of deaths by turbine pale in comparison to a national slaughter from a fast-spreading disease called white-nose syndrome, a malady caused by a white fungus that shows up on the muzzle, ears and wings of bats. The U.S. Fish and Wildlife Service estimates it has massacred millions nationwide.

Although the service hasn’t found white-nose syndrome in Iowa yet, its precursor – the fungus – has arrived. It was discovered in a hibernaculum in the winter of 2011-12.

The disease’s first U.S. appearance was in New York in 2006.

Since then, the white-nose syndrome swept through the northeast, slashing the bat population by 80 percent. It plunged through the southeast before racing westward at what the National Wildlife Health Center calls an alarming rate. The fungus turned up in Iowa and Minnesota in 2011-12, and then the disease struck Wisconsin last year. Just a few weeks ago, the fungus turned up in Oklahoma for the first time, achieving its westernmost reach to date.

“It is unlikely that species of bats affected by white-nose syndrome will recover quickly, because most are long-lived and have just a single pup per year,” the U.S. Geological Service reports on its web site.


The northern long-eared bat, a 3 1/2-inch critter slung between wings spanning 11 inches – gets hit so hard by the disease the wildlife service, effective May 4, listed it as threatened under Endangered Species Act of 1973 .

Initially, the service believed it faced extinction and listed it at the highest warning level – endangered – in October 2013 making it only the second bat visitor to Iowa to gain protection since the Indiana bat got protection status in 1967. But strong opposition to the 2013 endangerment listing from the wind, timber, oil and gas industries ensued, prompting the service to reduce the danger level to “threatened” earlier this year.

The lower danger level still means the northern long-eared bat’s future is bleak, that it is likely to reach the endangered point in foreseeable future if the killing continues at the current pace. But it gives the wildlife service more flexibility to relax prohibitions against killing bats.


In establishing temporary rules for an endangerment listing, the service exempted some activities, such as forest management and utility right-of-way clearance, but not wind power generation. It accepted public suggestions for changes in its rules through Wednesday, July 1.

While federal protection might be good news for bats that may not be the case for wind-power in Iowa and elsewhere, industry officials argue.

The industry is seeking relief from the rule, arguing that the cost impact would be out of proportion to the damage it does to long-eared bats in comparison to the white-nose syndrome.

“The risk posed to the species by wind energy is de minimus,” the American Wind Energy Association wrote to the Fish and Wildlife Service on March 13.

Closer to home, Mike Prior, head of the Iowa Wind Energy Association, told IowaWatch: “We want to take care of our avian friends and our bats. While we want to evolve wind energy in a way not to hurt wildlife, bat deaths are not a concern and will not impact wind energy.”

Wind turbines the evening of June 26, 2015, in southern Minnesota near the town of Alpha.
Wind turbines the evening of June 26, 2015, in southern Minnesota near the town of Alpha. Credit: Lyle Muller/IowaWatch


The decision to list the bat species as endangered, which does not exempt turbines from mitigation, could force wind operators in affected areas nationwide to spend about $610 million over the next 30 years, the American Wind Association complained, with support from the U.S. Chamber of Commerce. That cost would cover developing and maintaining a habitat conservation plan as required by the wildlife service to qualify for a permit called an “incidental taking permit,” allowing incidental killing or injuring of bats.

The federal wildlife service also is moving to protect the bats’ habitats, which are sometimes damaged during construction of wind farms. In June, it announced July meetings in Ames, Iowa, and seven other Midwestern states to gather the public’s ideas for drafting an environmental impact statement for the habitat conservation plan.

The states are working with the federal service on a regional habitat conservation plan for the northern long-eared bat, two other bats and several birds. The other states are Illinois, Indiana, Michigan, Minnesota, Missouri, Ohio and Wisconsin.

The environmental impact statement will analyze the possible environmental effects of issuing permits for the incidental killing of bats and other covered animals and of implementing the habitat conservation plan.


The wildlife service says the fungus causing white-nose syndrome affects 60 percent of the northern long-eared bat’s total geographic range, and it is spreading.

AAMAPIt ranges across 37 states, including Iowa, Nebraska, Oklahoma, Missouri, Illinois, Indiana, Ohio, Michigan, Wisconsin, and Minnesota. Northern long-eared bats have been captured in 13 of Iowa’s 99 counties, in central and southeastern Iowa since the 1970s, with eight more in west central and one in southwestern Iowa in 2011

The fungus – Pseudogymnoascus destructans, often written as Pd has affected seven North American bat species and spread into 26 states, including Iowa and seven other Midwestern states, according to the Federal Register.

In the Midwest, the disease itself has been documented in Illinois, Indiana, Wisconsin, Missouri, Michigan and Ohio. Although the fungus has been found on bats in Iowa, Oklahoma and Minnesota, experts have not yet found a bat in the three states that has been infected. Nevertheless, Iowa, Minnesota and now Oklahoma would have to abide by the prohibition against killing them, Georgia Parham, spokesperson for the wildlife service told IowaWatch.

Much of the wind industry’s argument for exemption from the rule for an endangered species listing is based on its lack of relative culpability.

John Anderson, a senior director for the American Wind Energy Association, said it is neither fair nor effective for the wildlife service to put “a conservation burden on activities that are not having a significant effect,” Midwestern Energy News, a non-profit, energy news website, reported recently. “The wind industry is one of them,” he said.


Whether wind turbines or the fungus are the worst bat killer is not a factor the Endangered Species Act lists for determining whether protections for a bat species should kick in.

The act requires the government to list a species for protection if its existence has become threatened or endangered by any one of five factors: disease or predation, man-made or natural activities, harm to its habitat or range, overuse or because existing protective rules are inadequate. Once a species is listed, the act prohibits people or corporations, including those who are not the primary culprit, from killing or harming them.

While the wildlife service acknowledges that wind turbines aren’t primary culprits in northern long-eared bat deaths, it contends that death by turbines already are “significant” and getting worse. Various studies through 2011 have generated estimates ranging 653,000 to more than 1.4 million as of that year with another 196,000 to 396,000 estimated in 2012.


In Iowa, the United States Geological Survey (USGS) calculated the adjusted mortality rate by examining bat deaths and activity at the 89-tower Top of Iowa Wind Resource Area near Joice in the north central Iowa’s Worth County from 2003 to 2004. In 2003, roughly four bats were killed per turbine per year. In 2004, that number jumped to about seven bats per turbine.


“My personal estimate is that six to 18 bats are killed each year per wind turbine,” said Bruce Ehresman, biologist for the Iowa Department of Natural Resources Diversity Program.

These numbers fluctuate within each region of the state, Russell Benedict, a professor of biology at Central College in Pella, Iowa, said. “I think Ehresman’s estimates are dead on, with the caveat that the number at any one turbine is going to depend somewhat on the surrounding habitat,” he said.

The American Wind Energy Association says Iowa has 3,447 wind turbines. If a minimum of four bats are killed per turbine, this results in 13,788 bat deaths per year. Using Ehresman’s maximum estimate, the toll rises to 62,046.

Whatever the toll is now, it is likely to grow as the wind industry continues expanding, particularly in Iowa, Oklahoma, Minnesota, Kansas and New York, which are among the top 10 wind energy states. Eventually wind energy is expected to provide 20 percent of the nation’s energy needs, the wildlife service said.


At wind farms, collisions with turbines and moving blades appear to cause the most deaths, but death caused by the vortex wake – known as barotrauma – is more difficult to estimate, according to wildlife service’s analysis in the U.S. Federal Register.

Wind turbines near Joice, in northern Iowa, on June 26, 2015,
Wind turbines fill the countryside near Joice, in northern Iowa, on June 26, 2015. Credit: Lyle Muller/IowaWatch
Wind turbines fill the countryside near Joice, in northern Iowa, on June 26, 2015. Credit: Lyle Muller/IowaWatch

Scientists determine whether barotrauma caused the death by examining the internal damage to bat carcasses that otherwise show no external evidence of collisions. A 2012 study found that 6 percent of the dead bats examined died from barotrauma.

A 2011 study showed how difficult it is to determine how many bats wind turbines actually kill, because turbine injuries may not cause death at the site. It found that 74 percent of the dead bats at wind turbine sites had bone fractures from apparent collisions with blades, towers or the turbine housing, called the nacelle. But, among that percentage, over half also had mild-to-severe hemorrhaging in the middle or inner ear, which destroys or diminishes the bats’ echolocation ability.

Echolocation is vital to bats’ survival because it enables them to navigate in flight, avoid collisions and forage for food. So, significant drops in air pressure behind the spinning blades causes inner-ear damage but often without immediately killing them. Nonetheless, the severe damage ensures their fatal fate, the wildlife service wrote in the Federal Registry.

The wind industry, looking at the more abstract, long-term, pictures itself as the friend of the bat.

“Wind energy provides important indirect conservation benefits by displacing the environmental impacts resulting from generation of electricity from non-renewable fuels, including carbon emissions that contribute to climate change, all of which potentially negatively impacts the species,” the American Wind Industry Association wrote in its comments to the wildlife service.


In seeking exemption from the wildlife service’s threatened species rule, the American Wind Energy Association has proposed adjusting turbine operations to reduce bat deaths.

Based on the theory that bats don’t get out in high winds, the association says facilities could hold off letting the turbine blades turn until the wind reaches a certain speed, known as “cut-in speed,” during migration periods and between certain times of the day.

Benedict, the Central College biology professor, also suggested coordinating turbine operations with wind speed.

“Instead of turning wind turbines on when winds reach 7 miles per hour, wind turbine companies could wait to turn them on when winds reach 9 miles per hour,” he said.

He estimated that would cut bat mortality by about 50 percent, but only hurt energy production by 3 percent. “If we are more careful about when we use wind turbines, we won’t have that big of an impact on energy production, but we can dramatically reduce bat mortalities,” Benedict said.

The Iowa Department of Natural Resources has established a set of interim guidelines to assist wind energy developers and producers to do a better job of designing and siting wind farms. The guidelines consist of recommendations on things that ought to be considered when developing wind energy farms, such as avoiding placing turbines near migratory patterns of endangered species.

In the meantime, scientists keep trying to figure out ways to stop the killings. The U.S. Fish and Wildlife service soon will give $250,000 in grants to research bat treatments’ safety, effectiveness and ways to mitigate the disease’s impact. It already has spent $20 million searching for cures and control of white-nose syndrome.

IowaWatch Co-founder Stephen J. Berry contributed to this report.

This IowaWatch story was published by The Hawk Eye (Burlington, IA), Fort Dodge Messenger, The Gazette (Cedar Rapids, IA) and Storm Lake Pilot Tribune under IowaWatch’s mission of sharing stories with media partners. To learn how IowaWatch’s nonprofit journalism is funded and how you can support it, go to this link.



Part of the challenge is learning how white-nose syndrome kills. Experts already know it strikes while the bats sleep.

“This fungus grows in hibernating bats and causes them to wake up earlier from hibernation, causing them to use too much energy and starve to death,” said Amber Schorg, a fish and wildlife biologist for the wildlife service.

The fungus thrives in cold environments where bats hibernate and where bat-to-bat transmission is the leading cause of its spread. It also remains in caves after an infected bat colony has left it to infect the next arrivals.


Iowa leads the nation in wind energy, generating 28 percent of its electricity from wind.

“It amounts to enough electricity to power 1.5 million homes throughout the year,” said Patrick Butler, principal investigator of the Iowa Alliance for Wind Innovation and Novel Development.

Prior, the executive director of the Iowa Wind Energy Association, asserted that he certainly wants to take care of bat species in Iowa, but he also likes to remind people of the positive impacts of wind energy.

Even though turbines are killing bats, he explained that between 6,000 and 7,000 jobs exist in Iowa that are directly related to wind energy.

“This amount of jobs in any industry is relatively large,” he said. “While this is a challenge, this isn’t necessarily a big concern like people want to make it out to be.”


But bats contribute to people’s well-being, too. They provide up to $53 billion annually to the United States by acting as a natural insect repellant for crops.

In Iowa alone, roughly $1 billion to $2 billion is saved each year due to their agricultural pest-eating duty, Rebecca Christoffel, a former natural resource ecology and management professor at Iowa State University, said.

Bats eat more than 2,000 mosquitos in a single night.

“They also are good for medical research,” she said. “They contribute to the development of navigational aids for the blind, birth control, artificial insemination techniques, vaccine production, and drug testing.”

To Benedict, the problem has a moral dimension.

“I personally believe that every organism on earth has just as much of a right to be here as I do,” he said.

“The fact that we humans are shoving a species off the face of the Earth at an incredibly fast rate is a reason to protect these bats. We have no right to be doing this in my personal opinion.”

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  1. Every wind turbine mortality estimate given to the media is based upon rigged research and contrived methodology designed to not find the most carcasses. Clearly the most dangerous thing about wind energy is………..Corruption, collusion, scientific fraud and a propaganda machine selling their lies.

  2. I agree with Russell Benedict–bats are Iowa residents too and deserve our protection. I find it a stretch to call industrial wind ‘green energy’ when it is responsible for killing millions of birds, bats, and raptors at an unprecedented rate for a man-made structure. Wind Energy claims their massive turbines have a minimal impact compared to the number of birds killed by cars and windows–this is so misleading. There is an estimated 250 million cars in America–even more windows! Consider this, a turbine kills an average of 12 bats per year–how many bats did you kill with your car last year? In your life? If wind lobbyists are willing to mislead about bird deaths, how else are they misleading us?

  3. Steve Cherry–this was a terrific article. Very informative. I would like to see more information about the wind energy ‘vital to Iowa.’ This industry often cites 6-7K jobs, but how many are full time with benefits? Pay a living wage? Permanent? Local? The actual percentage of Iowa’s energy from wind also deserves further research. The Energy Collective’s research shows that almost 18% of wind energy is lost in conversion before it reaches the end user (compared to 6.7% for other grid sources) (see Also, just because Iowa generates 25% of electricity from wind, do we need that much? I oftentimes see the turbines near our home standing idle on windy days because there is no need for the extra energy. Excess vs usable energy are two different things. One involves over production (which is wasteful) while the other is reality, which we need.

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