Bat and Bird Kills by Wind Turbines
Since the year 2000, industrial wind turbines have overtaken all other causes of mass mortality events for bats in North America and Europe – Multiple mortality events in bats: a global review
In the US, a conservative estimate of bat mortality indicates that at least 4 million bats have been killed by wind turbines since 2012. Bats are the primary natural defense in keeping mosquito populations in check. One bat can eat between 500 and 1,000 mosquitoes and other insect pests in just one hour, or about 6,000 per night – Bats, Artificial Roosts, and Mosquito Control
Most early work in tracking bird and bat deaths at industrial wind turbines focused on birds, especially eagles. Then, as large numbers of dead bats were discovered, researchers began to study how bats were being killed. Fish and wildlife specialists were stunned at the number of dead bats they found at industrial wind turbines in eastern US. It was discovered that about half the bat kills were from barotrauma: a bat only has to come close to a spinning blade, and the pressure change will burst the blood vessels in its lungs. – Bat Killings by Wind Energy Turbines Continue
About twice as many bats as birds are killed by wind turbines. Scientists estimate that 90% of the hoary bat population could be lost to turbines in the next 50 years – Bats Killed in Large Numbers at United States Wind Energy Facilities
Bats, it has been found, are attracted to wind turbines. It is thought it may be because these attract insects – https://wcfn.org/2013/07/24/Biodiversity Alert/
Mosquito populations rising tenfold
Mosquito populations have increased tenfold over the last 50 years according to long-term datasets from mosquito monitoring programs in several states – Anthropogenic impacts on mosquito populations in North America over the past century
As mosquito populations have risen, mosquito born viruses affecting humans including Zika are beginning to increase in the US, South America, and Europe. A University of Michigan Study found that bats could eat 32% of mosquitoes in a given area – Experimental Assessment of the Impacts of Northern Long-Eared Bats on Ovipositing Culex (Diptera: Culicidae) Mosquitoes
A conservative estimate based on this study reveals that the 4 million bats that were killed by wind turbines in 2012-2016 could have eaten as many as 4 billion mosquitoes in the US alone last year (1 bat eating 10 mosquitoes a night for 100 nights times 4 million bats killed by wind turbines = 4 billion *). In the US, areas that have mosquito born disease problems have begun aerial spraying campaigns using Naled, an insecticide banned in Europe.
* This is a very conservative estimate of the number of additional mosquitoes flying around due to wind turbine bat kills. Bat expert Merlin Tuttle reviewed these numbers and explained that bats are opportunists that will eat whatever is available. The University of Michigan study showed that bats can put a significant dent in mosquito populations (greater than 30% reduction). Marm Kilpatrick, whose study showed the total mosquito population has increased tenfold over the recent decades, wasn’t sure how much of the increase was due to reduced bat populations. I chose 100 nights for the estimate as a conservative average for the U.S., as southern states have mosquitoes year-round while northern states only have several months of active mosquitoes. The main point here is that if you kill millions of bats you will have BILLIONS of extra mosquitoes, some of which are disease carrying.
Global travel and trade have increased the probability that mosquito born diseases will become widespread in North America and Europe. An invasive species, the Asian Tiger mosquito, is capable of spreading Zika, West Nile, Equine Encephalitis etc., and has established firm footholds in the US and Europe. Concurrently, a study found that German wind turbines are depressing bat populations for thousands of miles across Europe – Wind Farm Facilities in Germany Kill Noctule Bats from Near and Far
In 18 countries in the European Region – in order of likelihood (highest to lowest): France, Italy, Malta, Croatia, Israel, Spain, Monaco, San Marino, Turkey, Greece, Switzerland, Bulgaria, Romania, Slovenia, Georgia, Albania, Bosnia and Herzegovina, and Montenegro – there is a moderate likelihood of local Zika virus transmission. In limited geographical areas, namely Madeira Island (Portugal) and the north-eastern Black Sea coast, there is a high likelihood of local Zika virus transmission – Zika virus expected to spread in Europe in late spring and summer: overall risk is low to moderate
The future doesn’t bode well for bat and bird populations, as the newest wind turbines are much larger and more powerful with blade tip speeds reaching 180 mph. Biologists expect large increases in bird and bat deaths from these newer machines, but voluntary methods to reduce bird and bat kills have not been effective. Yet many well intended countries and states continue to heavily subsidize industrial wind turbines. In December 2016, the US Fish and Wildlife Service went as far as extending wind farm operators permits up to 30 years allowing for the cumulative, nationwide killing of thousands of golden and bald eagles –
DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Eagle Permits; Revisions to Regulations for Eagle Incidental Take and Take of Eagle Nests Dec. 16 2016
These permits disregard the fact that eagles, like most raptors, are attracted to wind turbines.
In any event, many more will be killed than allowed under the “permits”, as enforcement is near impossible.
As for bats, we’ve seen that they are the most effective natural method of mosquito control. And mosquitoes are a growing problem: here is what the New York Times says about it:
“Mosquitoes are one of the deadliest animals in the world. Their ability to carry and spread disease to humans causes millions of deaths every year. In 2015 malaria alone caused 438 000 deaths. The worldwide incidence of dengue has risen 30-fold in the past 30 years, and more countries are reporting their first outbreaks of the disease. Zika, dengue, chikungunya, and yellow fever are all transmitted to humans by the Aedes aegypti mosquito. More than half of the world’s population live in areas where this mosquito species is present. Sustained mosquito control efforts are important to prevent outbreaks from these diseases. There are several different types of mosquitoes and some have the ability to carry many different diseases.”
As they kill each year millions of mosquito-eating birds and bats, wind farms will only make the problem worse.
– Birds and bats are being killed at an astonishingly increasing rate as the number of industrial wind turbines increase.
– Mosquito populations are rising at an alarming rate.
– Bat kills in one location can impact locations thousands of miles away.
– Bats are long lived and slow to reproduce. Scientists are worried that some of the most useful bat species (e.g. Hoary bats) will not recover and become extinct – Fatalities at wind turbines may threaten population viability of a migratory bat
– Birds and bats provide a natural way of keeping mosquitoes and other problem insects (e.g. Lyme disease ticks) in check.
– Mosquitoes spread diseases like Zika, Malaria, and West Nile Virus. These diseases are spreading throughout the US and Europe.
– Communities are beginning to increase chemical spraying, including aerial spraying of Naled over millions of acres in the US. Naled is toxic to bees and butterflies. The European Union banned Naled in 2012, citing “potential and unacceptable risk showed for human health.”
– Politicians and Industrial Wind companies are not going to give in easily, as billions of dollars (and euros) in subsidies are at stake.
Tom Kennedy, guest author.