Start receiving our award-winning magazine today!


The Bat Diaries

Reports from the Field

White Nose Syndrome, responsible for the death of more than a million bats in the Northeast, is ravaging Vermont's bats. White Nose Syndrome has been found in all hibernacula surveyed recently by the Vermont Department of Fish and Wildlife, including at three caves owned by The Nature Conservancy at Plymouth, Brandon and Dorset. Dave McDevitt, Southern Vermont Land Steward for the Conservancy, has been watching and reporting on the bats as he joins Department of Fish and Wildlife biologists on their surveys at the Conservancy caves.

Dave McDevitt's Bat Diaries

March 8, 2011:  I assisted with the final Conservancy hibernacula survey of 2011 with Vermont and US Fish and Wildlife biologists.
About a hundred yards from the cave entrance, I caught a quick glimpse of what appeared to be a bat flying off down the mountain. Not a good sign, to say the least. After finally reaching the cave entrance, and catching our breath, we dressed in our protective Tyvec suits and made our way down into the cave.
There was a handful of dead bats clinging to the rock crevices outside the gate, but nothing like a few years ago when there were hundreds that had succumbed to the elements.
After opening the gate door and carefully scooting along the icy rocks to where we could safely stand up, we flashed our lights across the cave ceiling and gasped at how incredibly empty the cave appeared.
We quietly made our way around what is called Guano Hall (the first large room just inside the gate) scanning the ceiling and side walls, looking into all the cracks and crevices and all the familiar places where we have seen bats in previous surveys.
The devastation that White Nose Syndrome (WNS) has wreaked upon this hibernacula is quite clear. After nearly an hour searching this room and the two smaller rooms in the back, we could only find 35 bats.
Last September when we brought the NBC News crew up to the cave, we counted 58 bats at the very beginning of their hibernation. During the 2010 winter survey in March, we counted a total of 112 bats. To bring all this sad news into perspective, let me give you the numbers for the pre-WNS survey of 2003.
In the three areas of the cave that we counted 35 bats in 2011, researchers in the 2003 survey found 1,370 bats – a 97% decline in the largest hibernacula in New England. Obviously there could still be many more bats deep within the cave, but these numbers should be representative of what’s going on throughout the hibernacula.
I’ll finish with a positive within a negative. Of the 35 live bats we found this year, none showed signs of WNS. There was one bat that had raw skin, but the remaining looked pretty healthy considering they are at the end of hibernation. At least there are a few bats that survived the long winter and WNS.
Note: Writer Elizabeth Kolbert joined the expedition. Read her account.

Feb. 22, 2011: The 2011 winter hibernacula surveys show further decline as White Nose Syndrome (WNS) continues to decimate Vermont’s bat population. Two of the Conservancy’s three hibernacula have been surveyed so far, and things do not look good for our resident bats. Plymouth Cave has seen its little brown bat population decline by a whopping 88% since WNS was discovered at this site last year. Researchers counted 608 little brown bats at Plymouth in 2009 (pre-WNS), while the 2011 survey was down to a mere 72 individuals. We were only able to locate a single tri-colored bat, and sadly we did not find a single northern long-eared bat this year.
Our 2011 survey of the Brandon Silver Mine shows even further decline. The little brown bat population here has seen a 95% decline since WNS arrived in 2009. Only four little brown bats were observed this year compared to 86 individuals in the 2009 survey. We could only locate one tri-colored bat and one small-footed bat during this year’s monitoring effort. Even more alarming, this is the second year in a row that northern long-eared bats were absent from this hibernacula.
Between these two hibernacula, we counted a total of eight bats that had the characteristic white fungus on them that is associated with WNS. We can only hope that some the few remaining healthy looking bats will somehow make it through this winter and possibly show resilience to this deadly disease. Sadly, WNS continues to march across the U.S and has now been confirmed in North Carolina and Indiana.

Watch this site for Dave McDevitt's updated chronicles of how WNS is affecting Vermont's bats. Read his essay on finding WNS in Vermont caves in the winter of 2010 and see his ongoing Bat Diary entries below.
April 20, 2010: WNS has been confirmed in Missouri. This part of the country has some of the most extensive cave networks and is home to hundreds of thousands of endangered bats. Also, WNS has now been confirmed in the Great Smokey National Park.  The cave in question, The White Oak Blowhole Cave, is the largest know hibernacula for Indiana bats in Tennessee and possibly the region.

March 11, 2010: In a moving essay from the field at Aeolus Cave, land steward Dave McDevitt reflects on what the latest survey results mean.

March 3, 2010
Plymouth Survey Shows Similar Results.

I wish that I had better news to report from Plymouth Cave, which was one of the few places in Vermont that did not show signs of WNS in 2009.  Unfortunately, WNS is now officially confirmed at our caves in Plymouth. 

Since surveys began in 1991 the number of bats had steadily increased reaching a high last year of 617, a stark contrast with this years precipitous decline to just 185. The three species that have used Plymouth regularly, are little brown, northern long-eared, and the tri-colored or eastern pipistrelle.

Little brown bats have been the most dramatically affected. From the bats that were low enough for us look at, we could clearly see the common white fuzz on their faces and arms, and they were fairly emaciated. I doubt they are going to make it much longer.  I sure wish that I could send you all some good news. Next week is the survey of Aelous, and for those of you who have been tracking this issue you'll recall the devastation we found last year. (See Feb 1, 4, 23, 2009 entries below).

February 17, 2010.
20-year Low for Brandon Hibernacula.

Survey results from Brandon went about as expected, things are playing out just as in other caves and mines in the region. 

Overall bat numbers are down from last year, with a 2010 count of 51 individuals compared to 137 in 2009.  All species numbers were down with the exception of a slight up-tick in Indiana bats. Northern long-eared bats were completely absent and the population of little brown bats has plummeted since last year. 
Surveys have been conducted here since 1992, and although the numbers of bats using this hibernacula has fluctuated over the years, this is the lowest number of individuals ever recorded. Despite the lower numbers, the condition of the mine looked pretty good.  We did not see any dead bats nor did we see any flying around at this time of year, a sure sign of distress.  However, WNS is still attacking our bats as we counted more individuals showing signs and symptoms of WNS, and far fewer bats overall.  

December 15, 2009
Report Unusual Bat Sightings

Help Vermont Fish and Wildlife by reporting sightings of unusual bat behavior or bat deaths.

November 15, 2009
Bat Population down 94.5%

"Two dozen small winter colonies in Massachusetts, New York, and Vermont show they have plummeted from 48,626 bats to 2,695 -- an average 94.5 percent decline -- since the outbreak began." Read the story in the Boston Globe.

October 28, 2009
Repopulation Experiment in Vermont Caves

Biologists will begin repopulating two Vermont caves with healthy bats from Wisconsin to determine if the disease exists after infected bats are gone.  The Burlington Free Press reports.

October 19, 2009
Recent Cave Surveys Report Further Decline

The Post Star recently reported that recent cave surveys in New York and Vermont reported dismal results.  Some hibernacula have lost 95 percent of their bats. During a survey last month of the Conservancy's cave in Dorset, Vermont - one bat was caught in three hours.  The same survey resulted in 900 bats caught in the same amount of time two years earlier. Researchers and scientists are working diligently to solve the mystery before it is too late.

September 8, 2009
White Nose Receiving National Attention

White Nose Syndrome received some much needed national coverage by CBS News.  There are shots of Vermont's Mt. Aeolus included in the video.

June 10, 2009
Scott Darling Makes a Case for Federal Funds

VPR interviews wildlife biologist Scott Darling about why he is lobbying for federal funds to support research on White Nose Syndrome.

May 11, 2009
U.S. Forest Service Closes Caves to Help Bats

NBC reported that the U.S. Forest Service is closing thousands of caves and former mines in national forests in 33 states in an effort to control a fungus that has already killed an estimated 500,000 bats. 

May 8, 2009
Funding for White Nose Syndrome Research

The U.S. Fish and Wildlife Service, Pennsylvania Game Commission and 11 states including Vermont have contributed $1.37 Million to fund research on White Nose Syndrome. The two year grant will support ongoing regional efforts to determine the cause of WNS, how it is transmitted and if it can be contained.

May 7, 2009
Citizen Reports of Winter Bat Activity Raise Alarm

Scott Darling states that citizens reporting sightings of bats flying during winter, landing on buildings, struggling to fly and dying on the ground continue to grow.  See his map of WNS bat sightings  this winter.

May 1, 2009
Help Protect Summer Breeding Grounds

The Conservancy needs to raise $95,000 to fund the protection of 178 acres at Otter Creek Swamps known as Bond Island. This parcel contains a maternity roost site for the federally endangered Indiana bat. Females tend to favor the large trees with shaggy or exfoliating bark that have some solar exposure to maintain optimal body temperature for them and their pups. Conserving summer breeding sites such as this are vital to bats survival.

March 26, 2009 
U.S.Fish and Wildlife Issues an Urgent Request

U.S. Fish and Wildlife requests that cavers curtail all activity in caves in any state affected by White Nose Syndrome.  They have reason to believe that the disease may be transmitted by humans.  There is no evidence that White Nose Syndrome poses a risk to humans, but the potential risks to bats to great to take the chance.

March 13, 2009 
White Nose Continues to Spread

Unconfirmed reports have surfaced about White Nose Syndrome symptoms in Viriginia caves.  This news comes shortly after the confirmation of the illness found in West Virginia and New Hampshire.  This is no longer just a northeastern problem.  And there is no telling where it will end.

February 23, 2009 
Thousands More Dead at Mt. Aeolus

Dressed in white suits and blue medical gloves, we snowshoed up to the cave at Mt. Aeolus.  It was 20 degrees and snowing, it and yet a handful of bats were flying around searching for food that they would not find. They will never survive the rest of the winter after expending so much energy.  Bats were landing in the snow, some crawling with great effort, others eating snow to stave off dehydration, and still others tumbled down the hill towards the bats that had already died. 

New York biologist, Al Hicks reached the cave’s gate first.  He asked if someone had stacked the dead bats at the mouth of the cave.  Vermont's Scott Darling replied “They’re just dying there”.  Mounds of bat carcasses had formed at the bottom of a snowy slope. 

When we reached the first chamber, the devastation was evident.  The floor was littered with dead bats.  One square foot could contain up to 300 bats, now imagine the entire cave floor.  There were thousands.    

The mission was to collect 500 little brown bat carcasses for the Museum of Natural History.  Anticipating a population crash and loss of genetic diversity, they are documenting the genetic make up of the species.  25 bats to a gallon zip lock bag.  It was not a glamorous task. 

The image of dead, dying, and emaciated bats is burned into my mind.  I can’t help but wonder if we are witnessing an extinction.

February 11, 2009 
White Nose Found in Brandon

While surveying the mine in Brandon yesterday,  we discovered a handful of bats that had all the physical characteristics of White Nose Syndrome.  Some had the white fungus on their nose and face, while a few had it on their wings.  Some of these also seemed to be in a much deeper stage of  torpor than other healthy looking bats.  Even more alarming was that one of the two Indiana bats found during our survey had the fungus on its nose.  We did however, see all six species of bats (Little brown, Big brown, Eastern Pipistrelle, Northern long eared, Small footed, and the Indiana bat) that hibernate in Vermont which may or may not be good news since the method of transmitting WNS is still unknown.   137 bats were counted, which is 29 more than the 2007 survey.  There were two folks from New England Cable News.  Watch the video.  

February 1, 2009
Grim News from Mt. Aeolus

News from the research team at Mt. Aeolus in the Equinox Highlands.  Things are looking very grim and it seems to be getting worse by the week.   They reported that bat carcasses could be seen up to 50m from the cave and thousands inside the cave.  Living bats were seen trying to cluster with dead ones and flying bats looked as if they had lost the ability to fly.  We are due to survey Aeolus again this month.

White Nose Syndrome has now also been confirmed at a cave in Dover as well.  The good news is that White Nose has not been found at the Plymouth Caves, nor at the privately owned cave in Brandon. We will be surveying Brandon soon so hopefully, I will have some good news to share with everyone... lets keep our fingers crossed! 

January 23, 2009
Plymouth Free of White Nose

I joined VT Fish and Wildlife Biologists on a visit to a cave in Plymouth and was relieved to see no evidence of White Nose Syndrome at this cave.  Reporter Candy Page of the Burlington Free Press joined us to report on the story.  

January 13, 2009
Mt. Aeolus Bats in Trouble

Scientists arrived at the cave and could see they were not the first to have been there.  Coyote and fox tracks were seen leading to the cave.  30 some bats were seen flying around the cave entrance. 

Researchers observed small amounts of the tell tale white fungus on the wings and muzzles of bats.  The symptoms were limited but were present to a greater degree than seen during last year’s winter visit to the cave.  Approximately 200 bat carcasses could be seen on the ground outside of the cave.  Bat mortality at the entrance of the cave and day time activity appear to have started earlier in the season compared to last year's findings.


  • Bats are the only mammals that can fly.
  • Bats have excellent eyesight perfect for long-distance homing.
  • Bats also use echolocation to find their way around. By emitting calls then listening to the echoes of those calls, they can determine where various objects are located in the dark.
  • Indiana bats tend to return to the same hibernacula every year. 
  • Hibernacula must be draft-free and maintain a stable temperature of under 50° F but above freezing for hibernation.
  • Bats hibernate as a way of survival as there are no insects for them to eat during the winter months.
  • Bats are beneficial! Bats consume billions of insects every year and at no cost to the agriculture industry who could use the help. They are also great pollinators and spreaders of seeds.


We’re Accountable

The Nature Conservancy makes careful use of your support.

More Ratings

x animal

Sign up for Nature eNews!

Sign Up for Nature e-News

Learn about the places you love. Find out
how you can help.

Thank you for joining our online community!

We’ll be in touch soon with more Nature Conservancy news, updates and exciting stories.

Please leave this field empty

I'm already on the list!

Read our privacy policy.