Little Brown Bat infected with WNS
Wikimedia photo
It is the worst of times for Myotis lucifugus, better known as "little brown bats". A few years back on two summer nights I had the good fortune to capture three that intruded into bedrooms of two houses in Fly Creek, New York. Method of capture was simple - one flew directly into my hand-held
pillow case. The other two were encouraged to fly in a lighted, closed off room. Once exhausted they landed and I picked them up with a pillow case. As I gently felt for one bat under fabric and touched a lump - it cried. Carefully I took each outside and with a soft swoosh they were gone into darkness. These were my three rescues - I remember their fear and fragile beauty.
Since then and hopefully learning - bats are enormously valuable, rendering great service; ". . . one little brown bat can ingest from 600 to 1000 mosquito size insects every hour." Overall the suppression of insects by bats provides a service to American agriculture valued at between 4 and 50 billion dollars. *
At about the same time as my rescues, White Nose Syndrome (the fungus Pseudogymnoaseus destructians) was discovered in caves in central New York State (2006-2008). These caves used by bats for winter hibernation are known as hibernacula. WNS infects a hibernating bat's muzzle, ears and wings. They awaken, burn energy, become dehydrated, emaciated and dead. Species affected besides the "little browns" are small footed bats (Myotis leibii), Indiana bats (Myotis sodalist) and others. The impact upon bats has been devastating. Since WNS emerged the bat population in the Northeastern United States has declined by 80% - with more than 6,000,000 killed. The little brown bat may now be en route to extinction. **
The Nature Conservancy owns the Aleolus Cave near Dorset, Vermont. Elizabeth Kolbert suggests that it may be the largest hibernaculum in New England and used by bats for winter hibernation since the end of the last ice age. Kolbert describes the scene inside the Aleolus Cave in 2009 as "horrific". She writes, "The ground was covered with dead bats; some of the ice knobs had bats frozen into them. There were torpid bats roosting on the ceiling, and also wide awake ones, which would take off and fly by or sometimes right into us." Bats are very social - one scientist watched a live bat trying to nuzzle into a group of dead ones. In 2013 the Vermont Fish and Wildlife Department posted signs at Aleolus, "This Cave is Closed Until Further Notice". Spreading from bat to bat and cave to cave WNS by September 2014 had reached 25 states and 5 Canadian provinces.***
The most recent issue of the Nature Conservancy Magazine (Oct/Nov 2015) contains an article "The Battle for Bracken Cave". It describes how conservationists and community members have united and successfully protected Bracken Cave, located near San Antonio from a plan to build 3500 homes nearby. Bracken Cave for eight months each year is home to ". . . the densest concentration of mammals on the planet." During this period between 15 and 20 million Mexican free tail bats fly out of the Cave each night in pursuit of 140 tons of agricultural insect pests. The exodus requires three hours and is a tourist attraction. Bracken Cave is also owned by the Nature Conservancy.****
I appreciate the efforts of the San Antonio conservationists, community leaders and support the Nature Conservancy, but was staggered by the absence of any mention of the WNS. Is the Mexican free tail bat immune to the fungus? Is Bracken Cave too warm to support WNS fungus? What is the prognosis for Bracken Cave and its millions of bats? So I clicked off the following email to the NC magazine. "Question: How can you publish an article about bats e.g. 'Bracken Cave' in 2015 and not mention the catastrophe of white nose syndrome?"
Eric Seeger, a Senior Editor promptly replied. ". . . While doing research for this article I asked many experts familiar with Bracken Cave whether white nose syndrome was a subject we should address in the article. They unanimously said no, and here is the general reason they gave: hibernation vs migration. White nose syndrome is a fungus that leads to the death of hibernating bats . . . the bat population at Bracken Cave consists mostly of Brazilian/Mexican Free Tail Bats. This is a migratory species that does not hibernate, so its populations have not been affected by white nose syndrome. And the experts I spoke to felt it will not become a threat to this species." Mr. Seeger also attached a link to a research report that claims some success in treating WNS.
http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/tennessee/success-in-treating-white-nose-syndrome.xm
My reply in part: ". . . As for the general reason . . . many experts gave . . . I hope to hell they are right."
Note; Bats and Rabies. The US Center for Disease Control reports that there are 1 or 2 rabies cases in the US each year. Of the 19 cases between 1997 and 2006, 17 were associated with bats. Among an unspecified number of bats captured by humans or cats and submitted for evaluation only 6 per cent tested positive for rabies.
*USGS/WildlifeHealth/WNS. Also FloridaEverglades.com
**Elizabeth Kolbert The Sixth Extinction:An Unnatural History Holt: NY; 2014 pp 180-186. Also USGS/WLH/WNS
***Elizabeth Kolbert. Also Wikipedia/WNS
****Nature Conservancy Magazine Oct/Nov 2015 pp 50-59.
