Wind Turbines Take Steep Toll On Birds And Bats

October 12, 2012
By Zulima Palacio
Voice of America

Wind power is key to efforts to produce clean, limitless energy and to slow global warming. It’s one of the world’s fastest-growing energy industries. But there is mounting evidence that expanding “wind farms” are taking a toll on airborne wildlife. Thousands of birds and bats are killed every year by collisions with the the wind towers and their giant blades. Environmental activists are taking the wind energy industry to court to find a solution.

Estimates by the Department of Energy indicate that in the United States alone, there will be more than 100,000 wind turbines by 2030.

John Anderson is policy director at the American Wind Energy Association. “As time goes on, I think you will see wind replacing older plants that are being taken offline, but we are really capturing the new installation market,” he said.

But wind energy developers, in California and West Virginia, are being sued by environmental groups. A growing number of groups contend that hundreds of thousands of birds and bats are being killed every year by wind turbines, mostly at night when bats and migratory birds fly around mountain ridges where many wind farms are located.

Kelly Fuller, with the American Bird Conservancy, said, “In 2009, an expert at the Fish and Wildlife Service estimated 440,000 birds were being killed by wind turbines a year. That was before we had more growth of the industry.”

West Virginia, in the eastern U.S., is a migratory corridor for birds. It’s also an important habitat for bats — millions of which have been dying from White Nose Syndrome. The illness has brought some species to the brink of extinction. Now they face another threat. This amateur video shows bats flying at sunset near wind turbines in West Virginia.

Judy Rodd is director of Friends of Blackwater, a West Virginia conservation group. She says this cave, close to a wind farm, houses thousands of hibernating bats during the winter. “The first year, they found 430 dead bats and I think 50 dead birds in a very preliminary sketchy study. The expert that analyzed those numbers, Dr. Tom Kunz from Boston University, estimated that finding 430 dead bats meant that actually 10,000 bats had been killed in one year,” she said.

That’s because the carcasses are scavenged by foxes, crows and other predators.

The U.S. government supports wind energy development to reduce the use of fossil fuels and to fight global warming.

David Cottingham is senior adviser at the U.S. Fish and Wildlife Service. He says the service does not have the authority to halt a wind project that’s on a migratory path. “But we do have the authority to prosecute them for violating the endangered species act,” he said.

Despite efforts to reduce wildlife collisions, no permanent solution has been found. The wind industry opposes shutting down or limiting turbine operations.

Industry, government, and environmental experts agree that choosing different locations for wind farms could be a good solution. But often the best wind currents are found in the paths that migratory birds and bats have been using for millions of years.

Troubling study indicates wind turbines may cause harm to bat population

NatSeptember 19, 2012
By Chris Clarke



A study published in a German scientific journal this summer indicates that wind turbines in one area may pose a serious risk to populations of bats over the better part of a continent. The study, performed by researchers from the Leibniz Institute for Zoo and Wildlife Research (IZW), showed that pipistrelle bats killed at German wind turbines likely originated from countries as distant as Scandinavia, Poland, the Baltic countries, and Russia. An estimated 200,000 bats are killed each year at German wind turbines, raising the possibility that Germany will become a sink for European bat populations — and raising troubling implications about the effect of wind turbines on California bats.

BatsBats in a cave in the Tehachapi Mountains | Photo: Random Truth/Flickr/Creative Commons License

The IZW researchers analyzed the fur of killed bats and recorded the ratio of stable hydrogen isotopes in the fur’s keratin. Hydrogen has two stable isotopes — a lighter isotope, H1, with no neutrons, and H2 or deuterium, which has one neutron in its nucleus. The two are chemically identical, but their ratio in the environment varies, with deuterium more common in the north of Europe. As an organism grows, it takes in deuterium in whatever ratio it is available in the environment, providing a geographical marker in the organism’s chemical composition. By matching the ratio of deuterium to H1 in fur samples then matching that ratio to a map, the researchers were able to determine where killed bats were raised.

As bats killed at German wind facilities may have come from places 1,000 miles or more away, and as bats have very slow reproduction rates of only 1 or 2 offspring a year, the study suggests that wind turbines in Germany may well be depressing bat populations across the entire northeastern portion of Europe, in an area perhaps a million square miles in extent.

The bats most vulnerable to wind turbine injuries — which seem to stem mainly from lung trauma from steep gradients in air pressure rather than from collisions — are migratory species that live in trees. In California, one of the most common tree bats is the hoary bat, which migrates in large groups across a wide swath of North America from Canada to Mexico. Though the hoary bat is unusual among bats in that it can have litters of three or four pups, the German study nonetheless suggests that poorly sited wind turbines in bat migration areas might depress hoary bat populations across the western part of North America.

A 2011 paper by Paul Cryan of the USGS Fort Collins Science Center in Colorado reports that bat deaths have skyrocketed with the advent of wind turbine installations:

Since 2004, unprecedented rates of bat fatalities have been documented at multiple wind energy sites across the United States and Canada, as well as in several European countries. In the United States, bat fatality rates at turbines are variable across sites and regions. Despite standardized and well validated methods for measuring and comparing fatality rates across sites rarely being employed, estimates to date for individual wind energy sites range from just below one bat per installed megawatt per year (bats/MW/yr) to as high as 70 bats/MW/yr. These fatality rates for bats generally exceed the fatality rates of migratory songbirds at wind turbines, and far exceed any documented natural or human-caused sources of mortality in the affected species of bats. Some large wind energy facilities (e.g., 100-300 MW) are estimated to have fatality rates of 10-20 bats/MW/yr, which means that single wind energy facilities are causing the deaths of thousands of bats per year. With approximately 40,000 MW of turbines currently installed in the United States and Canada, and an average published bat fatality rate of 11.6 bats/MW/yr, more than 450,000 bats may already perish at turbines each year in North America. This number might even be an underestimate due to problems with earlier fatality estimation equations and because bat fatality rates appear to be increasing with deployment of larger turbines. [Emphasis added.]

If U.S. wind turbines truly do pose more of a threat to some American bats than the dreaded White Nose Syndrome now devastating eastern Bat populations, then the German study is sobering indeed. It may be that even a few isolated wind installations may harm bat populations across a broad landscape.

As Cryan says, distressingly,

“In some parts of the country, bat researchers who only rarely catch hoary bats in the wild can now walk beneath turbines at certain wind energy facilities during autumn and find more dead hoary bats on the ground in a few weeks than they have caught during their entire careers.”

See original article:

Do wind turbines harm animals?

May 10, 2012 (San Diego’s East County) – With an increasing number of industrial-scale wind turbines around the world, numerous reports are surfacing to suggest that noise, infrasound and stray voltage (dirty energy) may be harmful to livestock and wildlife.

While evidence is largely anecdotal, incidences of mass die-offs of farm animals, chickens laying soft-shelled eggs, high animal miscarriage rates and disappearance of wildlife near turbines provide pause for reflection. These and other incidents suggest a need for scientific study to determine safety before additional wind energy facilities are erected across the U.S., including several proposed in San Diego’s East County.

Although wind turbines have been growing in popularity as an energy alternative in the 21 st century, there has been little to no testing done on the effects that these towering turbines could have on animals or for that matter, humans in the vicinity. We require testing of chemicals to assure safety before they may be used in the environment. Why is similarly rigorous testing not required to date for wind turbines?

Continue reading →

Effect of Wind Energy Development on Bats

April 27, 2012
by Jaclyn Aliperti & Morgan Nabhan
Boston University Undergraduate Science Magazine

Is wind energy really as “green” as we think?

Wind energy has gained widespread attention as a solution to reduce greenhouse gases. By 2020, it is expected that 12% of this country’s energy will be produced by wind turbines.1 While this may seem like a step in the right direction, there are environmental consequences. Bats, which play an enormous and often under-appreciated role in our ecosystems, are being killed by wind turbines in alarming numbers. Researchers predict that up to 111,000 bats will die due to wind turbines in 2020 in just the Mid-Atlantic Highlands region of the US.2 These deaths would not only pose an ecological problem, but would also prove to be an economic loss. In light of the economic and ecological value of bats and the growing popularity of wind energy, identifying ways to minimize bat fatalities on wind farms is essential.

Why Should Humans Care?
Although bats have a bad reputation for sucking blood, this misconception couldn’t be farther from the truth. Out of approximately 1,100 bat species, only three are known to feed on blood. Bats exhibit enormous diversity in diet and consequently provide varied ecological services, such as pollination, seed dispersal, and pest control. Nectar-eating bats encourage floral reproduction by transporting pollen on their bodies. Fruit-eating bats consume fruit and excrete the seeds, playing a significant role in promoting plant dispersal. Should bats fail to promote plant dispersal and reproduction, animals of higher trophic levels would starve. Insect-eating bats, which are of particular interest to us, are essential in regulating crop pests.

Three of the most affected bat species by wind turbines, from left to right – the Silver-haired bat, Hoary bat, and Eastern Red bat. Photos by J. Scott Altenbach.

battsFarmers rely on these bats to help increase crop yields. Researchers in Texas estimated the economic value of the pest-control service that bats provide to these farmers. According to their study, a lactating female bat can consume up to two-thirds of her body weight in insects in a single night.3 Considering that more than 100 million Brazilian free-tailed bats forage every night in Texas, the implications are enormous. Bats provide an economic service to farmers in two ways: first, they increase crop yield by reducing the number of pests, and second, they decrease the number of pesticide applications needed. Without these services, Texan farmers in the eight-county Winter Garden area would lose 13.5% of their annual income from the lost cotton production (worth an estimated $5.5 million/year).4 Moreover, pesticide use not only costs money, but also has its own environmental impacts. Increased crop pests make the possibility of organic farming less attainable. This analysis only accounts for the losses to part of Texas. On a national level, the economic losses due to decreases in bat populations would be devastating.

Why are Wind Turbines Killing So Many Bats?
Researchers currently do not understand why bat deaths occur in such large numbers near wind turbines. Hypotheses range from the poor placement of turbines to the idea that bats are attracted to wind turbines.2 One hypothesis proposes that clearing land to construct turbines may create a favorable foraging environment for bats by attracting insects to open areas. Another suggests that as the wind energy industry develops, taller turbines will expand into airspace that was previously occupied only by high-flying species of bats. Bats may be evolutionarily wired to seek out the largest tree on the horizon to serve as a potential roost and mating location. Thus, it is possible that bats mistake the large turbines for roost trees and fly toward them, only to be killed by the rotating turbine blades or the negative pressure that they create, which causes their lungs to rupture. Additionally, scientists believe that bats find the heat or sounds produced by spinning turbines attractive or disorienting. Despite these hypotheses, there is an urgent need for further research into the factors that influence bat fatalities on wind farms.

For such small animals, bats have unusually low reproductive rates, with an average mother producing only one or two young each year. At this rate, it could take decades to reverse dramatic losses to bat populations.4 The hoary bat, one of the most commonly killed species by wind turbines in North America, may not be able to sustain anticipated losses to its population within the next ten years.2

Finding a Solution
All too often, people are excited by the prospect of a new source of “clean” energy that they fail to recognize its negative externalities. Extracting wind energy where wind turbines do not conflict with migratory habits of bats could prevent significant fatalities. Knowledge about which factors are associated with increased bat fatalities could make it possible to improve wind turbine design and operations.

Research has shown that bats are more active on autumn nights characterized by low wind speed, low barometric pressures, and high cloud cover.5 During these nights, there are two methods that can be used to stop turbine rotation. First, turbines can be programmed to start moving once a threshold wind speed, or cut-in speed, has been passed. Second, in a method called feathering, the blades can be oriented so they don’t catch the wind. One study suggests that increasing the cut-in speed of wind turbines or feathering the turbine blades under these conditions can reduce bat fatalities up to 60%, while causing only a small loss in electrical power generation.6 The industry’s primary objection to such operational mitigation is loss of revenue. However, in the long run, if the wind energy industry fails to make such adjustments in their operations, a large decline in bat populations could be far more devastating economically and ecologically.

“Stopping wind turbines during low wind speed could reduce bat fatalities up to 60%

Other research findings present the possibility for further reductions in bat fatalities. Capping the height of turbines could also help prevent the exponential increase in deaths associated with increasing height.7 Another study suggests that painting turbines with non-UV-reflective paints could decrease turbine visibility at night and prevent bats from mistaking turbines for roost trees.8 Additionally, bats may be less likely to travel through an area with an induced electromagnetic field.9 Further research is needed to determine the effectiveness and feasibility of these potential mitigation methods.

In a major Federal court decision in December 2009, a judge in Maryland ruled to stop the expansion of a $300 million wind farm on the basis that it would kill endangered Indiana bats.10 This ruling would require the wind energy company to obtain a permit from the US Fish and Wildlife Service before constructing additional turbines. The permit would restrict the operation of wind turbines during peak periods of migration. Rulings like this serve as a reminder that renewable energy is not always synonymous with environmental sustainability.

As ongoing research reveals new solutions to solve the ecological problems associated with wind energy facilities, they should be implemented. Scientists at universities and various non-government organizations, such as the Bats and Wind Energy Cooperative and Cornell University’s Laboratory of Ornithology, are at the forefront of this research and are taking a stance by recommending changes in policies and operational mitigation. Bat fatalities caused by wind turbines will result in ecological discord and simultaneously harm the economic interests of farmers. We need policy changes to help realize the public benefit of bats. These changes need to ensure that wind energy is both environmentally and ecologically sustainable, while still being economically viable.

Windfarms: bird mortality cover-up in the UK

April 16, 2012
Save the Eagles International

egThe British public is being misinformed regarding bird mortality at wind farms, denounce Save the Eagles International (STEI) and the World Council for Nature (WCFN). It is contrary to fact to pretend that these industrial structures are “carefully sited” so as to avoid risks to birds and bats. It is equally false to allege that grouse and other ground-nesting birds don’t mind laying their eggs under wind turbines, or that raptors avoid these dangerous areas.

In a recent article, The Guardian states: “Studies in the UK had found evidence that birds of prey in particular avoided wind farms” (1). But if you look closely at the picture shown in the article, you’ll notice that the two birds flying between the turbines are raptors, red kites in fact, which were reintroduced in the UK at great cost. “So! – they avoid wind farms, eh?” – quips STEI’s President Mark Duchamp.

In Germany, where a few wind farms have been loosely monitored for bird and bat mortality, the government has disclosed the number of carcasses reported so far: 69 eagles, 186 kites, 192 buzzards, 13 harriers, 59 falcons, 12 hawks, 7 ospreys, plus hundreds more birds of all sizes and even more bats (2). “These figures are just a small sample of the ongoing massacre”, comments Duchamp, who cites this example: “Ubbo Mammen, an ornithologist commissioned by the German government, estimates that 200-300 Red Kites are being killed yearly by wind turbines in Germany” (3). These machines are driving many rare species into extinction, warns Mark.

In the UK, few raptor deaths leaked through what STEI calls “the windfarm cover-up”: three red kites, one osprey, and one sea eagle. “Officially, the eagle died of a heart attack”, mocks Duchamp. “In the UK, wind farms are not being monitored for bird mortality: this is how the issue is being kept from the public’s eye. Scavengers and wind farm employees dispose of the dead bodies, so it is extremely rare for a dead eagle or osprey to be found by some nosy trespasser.”

Birds and bats are being slaughtered by the million in other countries. In Spain, the ornithological society SEO/Birdlife recently estimated that the 800 Spanish wind farms were killing between 6 and 18 million birds and bats a year (4). Unlike birds killed by cars and cats, these include eagles and many other rare species.

But in the UK, bird charities hold the wind industry in great esteem, on account of global warming but also for their financial contributions to bird research, notes STEI. Hence the new study by researchers from the RSPB and BTO, which was just hailed by The Guardian in these terms: “Windfarms do not cause long-term damage to bird populations, study finds” (1). But raptors have been excluded from the study, remarks Duchamp. “As for the few bird species that were considered, the research is anything but convincing; besides, other studies have shown opposite results”. Mark remembers that, years ago, an RSPB officer wrote the following about the Edinbane project: “they (red grouse) have been known to collide with turbine structures and have shown population declines associated with windfarm developments elsewhere” (5).

The BBC, referring to the same study, recently proclaimed: “Wind farms ‘not major bird mincers’ ” (6). STEI wonders how this conclusion may be drawn from such an inconclusive and suspicious study, whose scope is not mortality, and only targets the “density” of selected non-raptor species. As for earlier claims that wind farms in the UK are “carefully sited”, Mark notes that many have been placed in the worst possible locations, where they will mince Scottish eagles into extinction: Eishken (aka Eisgein or Eisgen), Pairc, Pentland Road, Edinbane, Ben Aketil, various eagle ranges in Argyll, etc. “Hypocrisy and deceit are rampant,” laments Duchamp.

Mark Duchamp +34 693 643 736
President, Save the Eagles International
Chairman, World Council for Nature

Germany: How a dream became a nightmare

heartlMarch 8, 2012
A true story about the wind mania in northern Germany, of two people who moved to the countryside in order to realize their dream of a peaceful life and work in the midst of nature and now, 17 years later, find themselves in a permanent nightmare.

Paradise in the countryside to live and work
When we moved to the countryside in 1994 we were no wind power opponents. Generating energy through wind power could be useful, but we weren’t informed enough about pros and cons, so we wanted us to afford no opinion.

When searching for a suitable Farmstead on the countryside, we were interested in only one thing: a scenic and peaceful environment in a natural setting with a rich biodiversity and a vast horizon. This was what we found in the Wilstermarsch in the southwest of Schleswig-Holstein, the northernmost state of Germany in a small community that was named Neuendorf.

We had been townsfolk before but active friends of nature. Intact, natural surroundings with a wide variety of biodiversity of grassland birds, water birds and songbirds, birds of prey, owls and bats was an important criterion for us in buying an old farm which was in need of extensive renovation work. The associated garden was with no charm, unkempt, the adjoining land corresponded to the usual over-fertilized and nature-free agriculture standard.

In the southeast, a few hundred yards away, were standing three wind turbines, nearly 50 meters high, which attracted no attention, neither by noise nor by shadow flickers. We asked the farmer, who wanted to sell the house, if more wind turbines or other industrial buildings in the surrounding area probably are planned. He assured us that this was not the case.

The asking price for such an old house which was highly in need of renovation and the unkempt garden was too high. But the location was magical. A paradise like we dreamt of, in which we wanted to grow old and we were willing to invest much time and effort and to pay such an exorbitant price.

The nightmare began
10 months after our move, in the middle of our time-consuming renovation work and garden planning aimed at making our grounds as nature-friendly as possible to realize our dream, wind turbines were erected between 320 and 420 metres from our house.

First, the quality of life dies

The nightmare starlet and the consequences for us were the following:

  • Since 1995 we have to sleep with closed windows, because of the noise the wind turbines are producing – even when it is extremely hot. Relaxation and peace in our garden, on our land and with our animals is impossible when the wind blows – whether from south-east, east, northeast or northwest we can scarcely sleep even with closed windows. Conversation inside the house in certain rooms has been disturbed
  • Shadow flicker, something very special we’ve never experienced before, came into our lives between November and February. The turbines throw a shadow in the mornings which gives us headaches, induces irritability and disturbs our concentration (we have our offices at home)
  • The avifauna (wild birds, bats and insects) disappears. In February 1995, after the wind turbines started operating, the impact on the avifauna (wild birds, bats and insects) was immediately evident in a frightening way. The majority of birds and bats disappeared! Birds which are sensitive breeders, like peewits for example did not return after migration and the bats did not return from their winter quarters in the neighbourhood. Instead they disappeared permanently.

In order to work against this loss of wildlife we bought several hectares of land further away from the turbines on the other side of our farmhouse in the summer of 1995 and re-naturalized them. It took 5 years until the bird and bat population revived at a low level….

Reaction of the former conservation organizations: today’s enviro business
As members of various conservation organizations, we reported other members of our observations on the behavior of the avifauna, after the wind turbines started operating. Already at that time we were called crackpots. We were accused, we would be nuclear power lobbyists. The loss of species was partly denied, partly accepted without protest, because wind energy is such a good thing. We were horrified and took no longer part at meetings and activities.

Today we have left all the non-governmental organizations which are sponsored by industrial wind-profiteers and which became environmental companies with wind energy and biomass production at the expense of nature. We will support no longer this scandal and fraud on the expense of nature and the true conservationists.

Some did not answer the reasons for the termination, some answered with standard letters and others with incomprehension..

First symptoms of disease
Approximately 1996 we realized that we barely fall to sleep and weren’t able to sleep through the night. We thought even to ask a dowser, to determine if our bed is standing above a water vein. We moved furniture between several rooms, but it was the same everywhere.

Symptoms such as ear pressure and noise in the ears were suddenly our companions. Visits to the doctor and medications became the rule for us. – I began to wonder why I felt better on my long and exhausting tournees, than at home. During the work I recovered from my lack of sleep. Previously it was vice versa…

Wind power profiteers and their dirty methods
That same year, amid this new and terrifying experience, the then-mayor appeared with the representative of a wind power operator to to convince us of an extension of the wind energy area – in the midst of the most species-rich wet meadows around our land. With the words: ” It won’t be to your disadvantage…”, he tried to corrupt us. The men were shown the door.

Much later we found out that it was wagered in the village, whether we let ourselves buy by the wind energy profiteers, or whether our love for nature would triumph…

Also we were told about the 1.000 DM, the community representatives were paid in the early 90s for their approval to the first plans for the wind turbines next to our farm..

Thus we realized, why the seller of the property we’ve bought suddenly wanted to sell the farm. He was member of the local council and agreed to the wind power plans, pocketed the sum, and then hurried to look for naive clients, to buy his dilapidated farm for a lot of money before the wind turbines are built.

Slowly we came to know from personal experience and by reading the approval documents of the wind turbines next to us this dirty secrets of the supposedly clean wind energy …

And there should be a lot more.

Local participants sought for global study on wind farm impacts

August 21, 2011 (San Diego’s East County) – Like those proverbial canaries in the coal mine, chickens near wind farms may provide early clues to potential harm to health of humans and animals. That’s the contention of Hamish Cumming, a farmer battling proposed wind turbines near his home in Australia.

hensHe’s written a letter to East County Magazine seeking help from people living near wind farms locally (and in other locations) to document cases of shell-less eggs, dead chickens, or other animals that suffer internal hemorrhaging.

The “humble chicken” is common in rural areas near wind farms and can be easily monitored, Cumming says. Chickens under stress may produce a soft-shelled or shell-less egg that can’t be laid, killing the chicken. Such incidents have been documented near wind farms, says Cumming, who has also collected examples of livestock and a dog that died from internal hemorrhaging near wind farms.

“There are reports from many wind farm locations that chickens within a 3 km distance from turbines exhibit shell-less eggs during some weather conditions,” he stated. “Some locations have reported shell-less eggs or dead chickens that coincide with residents’ complaints about “noisy nights” from turbines.”

In fact, shell-less eggs are also known as “wind eggs.” According to Broad Leys Publishing, which specializes in books for poultry owners, a yolk-less wind egg may occur in a young pullet, but “wind eggs can also occur in older hens if they are subject to sudden shock.”

Chickens aren’t the only species suffering ill health effects from living near wind farms, Hamish says.

“So far there are several records of dairy cattle in Canada and Australia reducing milk output by as much as 30%,” he wrote.

The Discovery Channel ran a report on massive deaths among bats that suffered lung hemorrhaging when flying near wind turbines:

Goats in Taiwan, verified by the Taiwanese Department of Agriculture, have reportedly died due to stress-induced conditions within 2 km of turbines. “I have had reports of high levels of stillborn lambs and calves (up to 10%)…and stillborn horses in Australia and overseas, only after wind farms commenced operations,” he claims.

Wind farms may even be damaging to the family pet, he believes. “A dog was verified by Werribee Veterinary Hospital as dying from multiple organ fibrosis, believed to be stress-induced—and it was also within 2 km of turbines.”

Animals grazing near wind farms have also exhibited fibrosis, or hemorrhaging of major organs, when butchered, he observed. He believes this may explain why some native birds abandon habitat and cease breeding close to wind turbines.

That’s of serious concern to Cumming, who has endangered bird species nesting on wetlands at his New Zealand farm.

There have also been claims around the world of human health impacts in some communities near wind farms. Dr. Nina Pierpont, a Johns Hopkin School of Medicine trained physician and Princeton University PhD, has authored a book titled Wind Turbine Syndrome documenting serious health effects in people living near wind turbines due to low-frequency sound waves: The wind industry has disputed her findings.

Cumming seeks residents in East County and elsewhere around the world who live within 5 km of wind turbines to create a large data pool. Participants may already own chickens, or be willing to acquire them for the study. Cutting open a dead hen will expose the shell-less egg, if that is the cause of death, he said.

He seeks the following data:
1. How close the nearest turbines are to your chickens or slaughtered animals
2. How many turbines are within 5 km
3. Brand and size of the turbines
4. Name of the wind farm
5. Your country

Data may be sent to

Article courtesy of East Coast Magazine’s Miriam Raftery.

East County Magazine is also interested in hearing about local cases of animal hemorrhaging, wind eggs, or human health issues from people living near wind farms in San Diego’s East County: contact

Wind turbines as landscape impediments to the migratory connectivity of bats

April 14, 2011
by Paul M. Cryan


Unprecedented numbers of migratory bats are found dead beneath industrial-scale wind turbines during late summer and autumn in both North America and Europe. This paper by Paul Cryan discusses how conservation laws are inadequate for protecting bats.

Unprecedented numbers of migratory bats are found dead beneath industrial-scale wind turbines during late summer and autumn in both North America and Europe. Prior to the wide-scale deployment of wind turbines, fatal collisions of migratory bats with anthropogenic structures were rarely reported and likely occurred very infrequently.

There are no other well-documented threats to populations of migratory tree bats that cause mortality of similar magnitude to that observed at wind turbines. Just three migratory species comprise the vast majority of bat kills at turbines in North America and there are indications that turbines may actually attract migrating individuals toward their blades.

Although fatality of certain migratory species is consistent in occurrence across large geographic regions, fatality rates differ across sites for reasons mostly unknown. Cumulative fatality for turbines in North America might already range into the hundreds of thousands of bats per year. Research into the causes of bat fatalities at wind turbines can ascertain the scale of the problem and help identify solutions.

None of the migratory bats known to be most affected by wind turbines are protected by conservation laws, nor is there a legal mandate driving research into the problem or implementation of potential solutions.