Six of Connecticut’s nine bat species are now on our state’s endangered species list.  The Long-eared bat, once Connecticut’s most abundant bat, is now federally protected due to rapid decline directly linked to bat White-Nose Syndrome.


99% of Bats Dead


A recent report aired on National Public Radio quoted Connecticut Department of Energy and Environmental Protection (CT DEEP) wildlife biologist, Kate Moran as saying that a bat site in Western Connecticut has seen a 99% drop in the number of bats in 12 years and that of the 3500 bats counted living in one hibernaculum in 2007, only a few dozen remain today.  The data is consistent with other outbreak areas that now extend as far as Washington State, but which are predominantly located in New England and south along the Appalacian mountains. In the areas where the white nose fungus has been confirmed, as many as 90-100% of the bats have died.  In Connecticut, NPR reports CT DEEP biologists as saying that 100% of Connecticut’s bat caves are infected with the fungus that causes White-Nose Bat Syndrome. You can view a map of the latest U.S outbreaks of Bat White-Nose Syndrome here.

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What is White-Nose Syndrome?


White Nose Syndrome is a condition where bats are awakened from hibernation by an infection from a fungus called Pseudogymnoascus destructans or Pd.  The fungus attacks the skin of the bat while it is hibernating.  The infection causes the bat to  awaken during frigid winter weather and to expend precious fat reserves in its awake state, reducing its chances of successfully surviving the season. The syndrome is called ‘White Nose’ because one can see the white fungus growing on the noses of infected bats. There is no known cure.



Origins of White Nose Syndrome


No one knows the source of the epidemic, though the fungus has been identified in Europe and Asia (where curiously it does not affect bat populations), and genetic studies confirm a similarity between U.S. and Eurasian strains.  The fungal spores are especially hardy and could have been transported to America on anything including the clothes or shoes of humans.  In the U.S., the disease is most often transmitted from one bat to another, especially in the close confines of hibernaculums where bats pack together for winter hibernation, but according to Bat Conservation International, a recent outbreak in Washington State, approximately 1300 miles from the westernmost detection in Nebraska, has researchers concerned that the disease is also being transported by humans.  Though the Washington State infection site is near an International airport, the genetics of the fungus in Washington show that the Washington strain’s genetics ‘most closely matched fungal strains from eastern North America.’  Because bats do not travel that far, the data hints that the vector of the disease may have been a person that had the spores on his or her clothes.


Spread of White Nose Syndrome in America


White Nose Syndrome was first identified in bat cave in Albany, NY in 2006 and by 2007-2008 it was identified in neighboring Vermont, Connecticut, Massachusetts and Pennsylvania.  The disease has steadily made its way south along the Appalachian mountains and west, especially in the northern latitudes of the U.S., and across Canada.  The disease has also been confirmed in Texas, parts of the midwest, and Washington State.




Which Connecticut Bats Are Affected by White Nose Syndrome?


According to CT DEEP, eight species of bats can be found living in Connecticut:


  • Little Brown Bat (Myotis lucifugus)
  • Big Brown Bat (Eptesicus fuscus)
  • Eastern Long-eared Bat (Myotis septentrionalis)
  • Eastern Pipistrelle (Pipistrellus subflavus)
  • Silver-haired Bat (Lasionycteris noctivagans)
  • Hoary Bat (Lasiurus cinereus)
  • Red Bat (Lasiurus borealis)
  • Indiana Bat (Myotis sodalis)


The DEEP’s list of  Endangered, Threatened, and Concerned Species in Connecticut confirms that all of these species, except the big brown bat, are now listed as endangered under the Connecticut Endangered Species Act. In addition to making the state’s endangered list, the Eastern Long-eared bat, once one of Connecticut’s most populous bats, is now on the federal ‘threatened’ species list and the Indiana Bat is on the federal ‘endangered’ list.


Connecticut’s Eastern Pipestrelle Bat, now endangered because of White-Nose Syndrome. Here the bat is shown hibernating inside the walls of a homemade bat box. For instructions on how to build or where to buy a bat box, scroll down.


Environmental Impact of White Nose Syndrome on Connecticut


According to the U.S. Fish and Wildlife Service, “ WNS has killed millions of North American bats in recent years, decimating many populations and putting several species at additional risk of extinction. Bats are crucial to our nation’s farmers and foresters, helping control pest insects such as beetles and locusts, and significantly reducing the amount of toxic pesticides that would otherwise be needed. Studies estimate bats save farmers at least $3.7 billion per year in lost crop revenue and pesticide savings.”


According to CT DEEP, a single little brown bat can consume 1200 mosquitos an hour.  Though elsewhere in the world, bats are a significant source of pollination, In the U.S they are considered by many ecologists to be one or our most potent and safest sources of insect control.  In an article published in the New Haven Register, biologist, bat expert, and associate professor at Southern State Connecticut College, Miranda Dunbar, mused that a reduction in bats may lead to a higher rate of mosquito borne illnesses like malaria, or canine infections like Heartworm disease. Said, Dunbar, “It begs the question of malaria and other mosquito-borne illnesses that could require attention in the future…It’ll be interesting to look at bat decline and whether there’s an increase in West Nile Virus.”


How Do I Help the Bat Population in Connecticut?


One hopeful finding of research by CT DEEP biologists is that the White Nose Syndrome fungus, Pd, is sensitive to changes in temperature and moisture.  Several of the Connecticut caves where Pd was found had microclimates where no Pd was isolated.  This suggests that installing bat houses around your home may provide bats a safe, disease free space because they have humidity and temperature levels different from the caves where Pd prefers to grow.


How To Build or Buy A Bat House


Bat biologists Jim Kennedy stresses that most commercially bought bat houses are not designed properly.  When considering building or buying a suitable bat house, he suggested that one use the resources located on the Bat Conservation International website where houses can be built or bought with the two things most important to bats: a range of temperatures and safety from predators.  You can view Bat Conservation plans to build your own bat house, or use this page to find a seller of bat homes approved by the conservation organization.

This is a great video. It’s filmed in fast-motion so that you can quickly see all of the essential elements to building the right kind of bat house.  The designer seems to have taken most of his inspiration from the designs that are available on the Bat Conservation website.

Report Signs of Bats Flying In Winter Or Living Near You


If you see bats flying during the winter time (typically a sign of infection by the fungus that causes White-Nose Syndrome) or if you have bats roosting in your area, the CT DEEP wants to hear about it. Learn more on how you can help Connecticut wildlife officials understand how White-Nose Syndrome is affecting Connecticut’s bats.

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