Dec 26, 2012

Bats Threatened by White-Nose Syndrome

Bats Threatened by White-Nose Syndrome


By Gayle Pille


Whether you like bats or not, there is no denying their benefits.  The little bug zappers have been around since the days of the dinosaurs and eat anywhere from 50 to 100 percent of their body weight nightly.  A single Big Brown Bat can devour up to 7,000 mosquito-sized insects a night.  A colony of 150 Big Browns can consume more than a million insects a year.  Put that in dollars and cents and the economic benefit of bats to the agricultural industry is approximately $22.9 billion per year.  Without this natural means of pest control, insect populations would explode.


But bats are facing a threat in North America like they have never faced before.  A fungus, almost certainly from Europe and probably transported into a cave on a visitor's boots or gear, is devastating eastern bat populations.  The disease, called White-Nose Syndrome (WNS), was first discovered in a New York cave in 2006.  Now, only six years later, WNS has spread to four Canadian provinces and 19 states, including Kentucky and all of our bordering states.


White-Nose Syndrome is a cold-adapted fungus that affects hibernating bats while in their hibernacula.  A white fungus occurs on an affected bat's nose, ears and wings attacking the skin and fur and causing severe tissue destruction.  The fungus appears to "itch" the bats forcing them to arouse regularly from hibernation and behave erratically.  Many leave the warmth and safety of their cave in the dead of winter.  This disruption to their hibernation cycle depletes much needed fat reserves, prematurely causing the bats to freeze or starve to death. 


Mortality rates are staggering.  Many eastern caves have experienced 90 to 100 per cent mortality.  To date, between 5.5 and 6.5 million bats have perished.  Biologists have described it as "the most precipitous wildlife decline in the past century in North America."  To make matters worse, the disease keeps spreading and is now as far west as Oklahoma.


Bats that hibernate in caves in tight clusters are most at risk, including Eastern Pipistrelles, Northern Bats, Little Brown Bats, and endangered Indiana Bats and Gray Bats.  However more solitary species as Big Brown Bats and Long-eared Bats are also experiencing severe losses.  Many species are expected to go extinct regionally in some parts of North America.  And for those that do rebound, it could take decades or even centuries for them to make a comeback.


If you want to help bats and control local insect populations organically, install a bat house.  Bat houses offer one of the best opportunities for survivors to successfully reproduce. 

Contact Gayle at her website for nest boxes at or

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