Surveys performed this winter by researchers at the Vermont Fish
& Wildlife Department indicate that populations of several
species of bats in Vermont continue to shrink due to the
devastating effects of white-nose syndrome, a fungal disease
affecting cave-hibernating bats.
Fish & Wildlife scientists Scott Darling, Joel Flewelling,
and Alyssa Bennett spearheaded a statewide survey of Vermont's
cave-hibernating bat species to continue monitoring the disease
since it first hit the state. They have witnessed the effects
of the disease, which was first detected in eastern New York in
2006 and was confirmed to have infected Vermont's bats by 2008. The
disease has since spread as far away as Missouri and Nova Scotia in
"We've recorded declines as high as 90 percent during our cave
surveys, so we feared a continuation of that drastic rate of
decline this winter," said Darling. "While the rate that we're
losing bats each year appears to have slowed a bit, bat numbers
were still considerably lower than in previous surveys. Some
species, such as northern long-eared bats, are hardly appearing at
all in these caves."
Bats generate an estimated $3.7 billion a year in benefits to
North American agriculture through insect pest control and crop
pollination, according to the journal Science. In Vermont, they eat
insects that damage crops, torment livestock, or are forest
pests. "These unique mammals are the principle predator of
flying insects in New England," said Darling.
"The free-fall of bat populations due to white-nose syndrome is
something that should be on everyone's radar right now," said
Darling. "We're observing the most precipitous decline of a
group of species in recorded history and it's happening right here
in our region. Several species have virtually disappeared in
less than a decade and we are getting increasing skeptical that
these bats will ever return."
Vermont is home to nine bat species; six species spend winters
hibernating in caves and three migrate south. While the
species of bats that migrate may be threatened by increased
ridgeline wind development, population data on this suite of
species is very difficult to obtain. Among Vermont's cave
bats, the little brown bat and northern long-eared bat are state
endangered species, small-footed bats are state threatened, and
Indiana bats are state and federally endangered species.
According to Darling, there are three avenues to prevent these
species from becoming completely extirpated in Vermont. The first,
and best option, would be for researchers to find a treatment or a
cure for white-nose syndrome and a feasible means of applying it in
Alternatively, these bats may continue to decline until the few
that remain happen to be naturally resistant to the disease.
The Vermont Fish & Wildlife Department is participating in a
regional study to investigate this possibility. Alyssa
Bennett, wildlife technician, cites two adult female little brown
bats that the team recaptured six years after they were initially
captured and banded by researchers, despite the fact that most
other bats in their maternity colony had fallen victim to
white-nose syndrome in that time.
"While these individual bats may be genetically resistant to
white-nose syndrome, they may have also survived due to luck or
resilience, or by escaping exposure somehow," said Bennett.
The third option, which Darling refers to as the "Noah's Ark
strategy," involves holding the bats in captivity during the short
time period when they are most vulnerable to white-nose syndrome.
The department is working with other agencies to determine the
feasibility of such a practice.
"The struggle to save Vermont's bats continues to be a race
against time," said Darling. "If we're not successful with
these efforts, it's unclear what we'll turn to next."
Vermonters can help bat researchers in their effort to save bats
by donating to the nongame wildlife fund on line 29 of their tax
return or by going to www.vtfishandwildlife.com.
Photos by Tom Rogers, Vermont Fish & Wildlife