ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...

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ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
ECHOLOCATOR                                        Volume 10
                                                      Issue 1
                                                    Feb. 2021


                   In A World Turned Upside Down

  Thank You For Helping Us Through 2020
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
2         Wisconsin Bat Program • 2021

                                  Table Of Contents


 5                                                                                      8

Wisconsin Bat Program
                                                                                       The Wisconsin Department of Natural
                                                                                       Resources (DNR) provides equal opportunity
                                                                                       in its employment, programs, services and
 3       Editor’s Note                                                                 functions under an Affirmative Action Plan. If
                                                                                       you have any questions, please write to Equal
                                                                                       Opportunity Office, Department of Interior,
4        Q & A With Bat Team Leader                                                    Washington, D.C. 20240. This publication
                                                                                       is available in alternative format (large print,
 5       Winter Surveys Show Average 89% Drop                                          Braille, audio tape, etc.) upon request. Please
                                                                                       call 608-261-6449 for more information.
                                                                                       Echolocator is an annual publication of the
 7       Cave & Mine Catalogue Update                                                  Wisconsin Bat Program, part of the DNR’s
                                                                                       Natural Heritage Conservation Program. DNR
8        Acoustic Bat Monitoring Update                                                conservation biologists statewide monitor,
                                                                                       research and inventory Wisconsin’s eight bat
                                                                                       species in collaboration with other state and
14       Wisconsin-Based Research                                                      federal agencies, universities, conservation
                                                                                       groups, other non-governmental
15       Diet Study Reveals Bats’ Importance To Ecosystem                              groups and hundreds of volunteers.

                                                                                       Echolocator presents bat conservation work
18       Bats With White-Nose Syndrome Prefer Suboptimal                               and research relevant to Wisconsin and
         Habitats Despite The Consequences                                             welcomes ideas for future articles and featured

                                                                                       Please contact
                                                                                       to share your suggestions.

                                                                                       Editor, Jennifer Redell
                                                                                       Graphic Design, Rebecca Rudolph

                                                                                       State of Wisconsin
                                                                                       Department of
                                                                                       Natural Resources
In a world seemingly flipped upside down, reaching out                                 Box 7921
to friends helped us get by in 2020. These hibernating                                 Madison, WI
little brown bats paired up to make it through the winter.
Photo, flipped for effect: Heather Kaarakka

ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
3        Wisconsin Bat Program • 2021

Reflections From The Editor

                       Hundreds Of Volunteers
                         Fly In To Help Bats
                                            “What remained
         By Jennifer Redell                                                      Some of our typical winter 2021 work
   DNR Conservation Biologist, Bat                                               remains on hold due to COVID-19. Our
  Program Cave and Mine Specialist                                               routine winter hibernation surveys
                                            constant, however,                   will be much more limited in the
Similar to most people, COVID-19            was the dedication of                coming months while we wait our
impacted our work in direct and                                                  turn for the COVID-19 vaccine and
indirect ways. Some things looked           the volunteers who                   the possibility of again searching
the same, many tasks were modified          play a vital role in                 caves and mines with colleagues. Our
or dropped, and we forged ahead
using technologies allowing us to
                                            helping us understand                longstanding safety practice has been
                                                                                 to search underground hibernacula
track bats remotely. What remained          the changes we’re                    only with a group of people.
constant, however, was the dedication       seeing in Wisconsin
of the volunteers who play a vital                                               We’re capitalizing on technologies
role in helping us understand the           bat populations due                  that allow us to track bats and learn
changes we’re seeing in Wisconsin           to WNS.                              more about them remotely. Relatively
bat populations due to white-nose
syndrome (WNS).
                                        of Wisconsin-Madison has been
                                                                        ”        new antenna systems installed at
                                                                                 several hibernacula will allow us
                                                                                 to read the activity of bats carrying
Despite the many challenges of the      instrumental in our understanding of     Passive Integrated Transponders
past year, Wisconsin Bat Program        bat diets in Wisconsin, and how little   (PIT) tags. As we move into summer,
volunteers monitored more roosts        brown bats are especially important      thermal cameras and PIT tag readers
and completed a greater proportion      for filling an important role as an      will help us better understand what’s
of acoustic surveys during a            ecosystem predator and for their         going on inside roosts.
significantly shortened monitoring      voracious consumption of agricultural
season. This work from dedicated        pests and mosquitos. She summarizes      As bats emerge from caves on to the
volunteers is critical in helping       her research in this issue and we wish   landscape and migrate home from
us observe how populations are          her well as she begins work at the       other states where they over-wintered
responding after WNS caused severe      University of Wyoming to improve         later this spring, we hope our outdoor
declines at the majority of Wisconsin   how chronic wasting disease in deer      summer work can be conducted in a
hibernation sites beginning six years   can be studied.                          mostly normal way.
                                        Researchers Skylar Hopkins, Kate         Whatever may come, we remain
Our streamlined newsletter              Langwig and Joseph Hoyt of Virginia      especially grateful for the dedication
summarizes these surveys and            Tech publish results of their long-      of, and the inspiration provided by,
other core activities and highlights    term study to see if bats alter their    hundreds of volunteers working
two key partnerships. Amy Wray’s        roosting preferences in hibernacula in   individually or with members of their
doctoral research at the University     response to the arrival of WNS.          household to help Wisconsin bats.
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
4        Wisconsin Bat Program • 2021

                 Bat Q & A With J. Paul White
Right now, Wisconsin’s four cave bat
species are in their winter hibernation
sites. Since white-nose syndrome
was first detected in a Grant County
mine in 2014, the disease has spread
to hibernation sites statewide and
resulted in dramatic decreases in
overall bat populations, with losses
at sites ranging from 70-100 percent.
Little brown bats, eastern pipistrelles,
also known as tricolored bats, and
northern long-eared bats have been
hit hardest while big brown bats have
fared better.

We catch up with J. Paul White, DNR
Mammal Ecologist and Bat Program
                                            Northern-long eared bats have fared the worst from
Lead, to understand the latest news
                                            white-nose syndrome. Photo: Heather Kaarakka
for Wisconsin bats.

Q: Where are Wisconsin bat                                                           sense to manage forest 100 miles
populations today?                         Q: What’s next?                           from a hibernaculum when species
J. Paul White: The picture is still        J. Paul White: Our mission is to work     typically migrate shorter distances.
developing and we see both signs           with others to identify, protect,         Identifying core use areas by bats is
of encouragement and cause for             monitor and manage populations            also critical for understanding best
concern.                                   of native bat species; enhance            management practices for forests, as
                                           and restore their habitats; address       bats have been shown to return to the
We incorporate survey data collected       human-bat coexistence, and promote        same summer habitat in consecutive
by volunteers, agencies and partners       knowledge, appreciation and               years. In addition, little to nothing is
from winter hibernation sites, summer      stewardship of bats in Wisconsin for      known about the connection between
maternity roosts, and state-wide           present and future generations.           winter hibernacula and active
surveys using acoustic detectors to                                                  summer habitat for most bat species
record bat calls along set routes.         Guided by the national plan and           in North America.
Together these data describe a still       the DNR’s strategy, Wisconsin’s
vulnerable cave bat population,            conservation and recovery efforts will    Q: What can I do to help bats?
prone to choosing “ecological traps”       be prioritized to protect our sensitive   J. Paul White: Bats continue to
where seemingly suitable hibernating       bat population during critical points     need our help as white-nose
conditions are just a deadly disguise      in their life -- hibernating or raising   syndrome, among other threats,
(read more about research into             pups -- while controlling the disease     exist in Wisconsin and throughout
these ecological traps on page 18.)        (vaccine development) to the point        the midwest. From respecting their
Yet, in some areas, we see resilience      where bat populations may recover.        privacy in the winter, to engaging in a
through summer and winter colonies                                                   citizen-based bat monitoring project,
alike, as numbers appear to have           Q: Broadly, what are the research         to installing bat houses to support
stabilized after hitting bottom. We’re     questions we need answers for to          these voracious insect-eaters, each
also seeing welcome signs of juvenile      better advance recovery?                  little action can have a positive
recruitment, which means some              J. Paul White: Understanding distances    impact on learning more about their
individual bats choose wisely in their     traveled and how bats use the             populations and/or supporting their
hibernation strategies and/or are          landscape surrounding permanent           survival as an important part of
genetically better suited to cope with     hibernation sites during movement         Wisconsin ecosystems. Find more
the deadly fungal pathogen causing         between winter and summer habitat         information about ways to help on
white-nose syndrome.                       can aid management decisions for          this Bat Frequently Asked Questions
                                           species. For example, it makes little     web page.
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
5                        Wisconsin Bat Program • 2021

   Winter Surveys Show Average 89%
   Drop In Bat Populations At 55 Sites

  DNR staff and Virginia Tech researchers count
  hibernating bats in Wisconsin in 2015.
  Photo: Joseph Hoyt

         By Jennifer Redell                                         55 sites in early 2020.                              with smaller populations reduced by
   DNR Conservation Biologist, Bat                                                                                       WNS to zero bats. Declines averaged
  Program Cave and Mine Specialist                                  Hibernating bat populations                          89% from their pre-WNS average
                                                                    previously exposed to WNS,                           populations at specific sites.
Wisconsin Bat Program staff collected                               particularly in years two and three
data on bat populations, species and                                of WNS infection, observed steep                     Wisconsin’s only site in its seventh
distribution from bat hibernacula                                   declines. We continued to see bat                    year since infection still had four
infected with white-nose syndrome at                                populations in some hibernation sites                bats hibernating in it, including one

                                                       Bat population at hibernation site where WNS was first detected in Wisconsin
                                                                                                                                                          Little brown bat

                                                                                                                                                          Big brown bat
                 1000                                                                                                                                     Eastern pipistrelle

                                                                                                                                                          Northern long-eared bat

                 800                                                                                                                                      TOTAL (all individuals)

                 600                                                                                                                                2009- tree down over entrance

                                                                                                                                                    2014- WNS detected in March
                                                                                                                                                    2015- WNS second year

                 200                                                                                                                                2016- WNS third year

                        1994     1996   1998   2000   2001   2003     2005   2007   2009   2010   2011   2012   2013   2014   2015    2016   2017       2018        2019        2020
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
6         Wisconsin Bat Program • 2021

northern long-eared bat. That handful       These datasets have been entered
of bats found in 2020 represents a          into the Cave & Mine Catalogue
                                                                                            Sobering Numbers
99.5% reduction from the site’s pre-        and added to the Natural Heritage
WNS average. Since the disease was          Inventory, where the location and
first detected in 2014, at least 64 sites   other information will help the state    •   35 U.S. states and 7 Canadian
in 25 Wisconsin counties have been          and private citizens protect and             provinces confirmed with
confirmed as WNS-positive or WNS-           manage them. Key findings from the           WNS
suspect.                                    site visits are highlighted below.       •   4 more states confirmed with
                                                                                         the fungus P. destructans
                                                                                         (Pd), causing the disease
                                                                                     •   12 bat species confirmed
                                                                                         with WNS, 6 more with Pd
                                                                                     •   5.7 to 6.7 million bats
                                                                                         estimated dead of WNS as of
                                                                                     •   Wisconsin: 64 sites in 25
                                                                                         counties confirmed as WNS
                                                                                         positive or WNS suspect.
                                                                                     •   Bat population changes have
                                                                                         ranged from minor increases
                                                                                         at a very few sites to 100%
                                                                                         declines where no bats
                                                                                         remain in a given cave or

  Notable Observations In 2019-2020             pre-WNS average.
         Hibernation Season                 •   The site where WNS was first
                                                detected in Wisconsin, now in
  •       White-nose syndrome has now           its seventh year of infection,
          affected cave bat populations         has experienced a 99.5%
          in Wisconsin for seven                population decline when
          hibernation seasons and the           compared to baseline data, as
          WNS fungus is considered              see in the graph on page 5.
          present in hibernation sites      •   The DNR has focused
          statewide.                            on understanding bat
  •       Two of Wisconsin’s largest            survivorship, immigration/
          surveyed sites are down 87%           emigration and fidelity to
          and 71% from their pre-WNS            hibernation sites. To this end,     Photo: Jennifer Redell
          average populations. Both             DNR and our Virginia Tech           Condensation forms on an
          sites originally held tens of         partners banded over 1,800          eastern pipistrelle bat.
          thousands of little brown bats        bats between fall 2019 and
          and other species. Both sites         spring 2020.
          are now in their fifth year of    •   We continue to locate a few
          infection.                            “long-term survivor” bats in
  •       Hibernacula now in year six           the sites where they were first
          of disease progression have           banded before discovery of
          experienced an overall decline        WNS in Wisconsin in 2014.
          of over 89% compared to the
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
7        Wisconsin Bat Program • 2021

            Cave & Mine Catalogue Update
   Wisconsin’s Bat                        year we continued to provide support
                                          to the project, the goal of which is
  Data Aids National                      to determine if immunization of bats
                                          against WNS improves their survival
   Species Status                         and/or reduces the occurrence of
                                          the disease. In 2020 two potential
    Assessments                           vaccine candidates were tested for
                                          effectiveness in little brown bats
         By Jennifer Redell               in the field. Additionally, timing
   DNR Conservation Biologist, Bat        of vaccination was tested, both at
  Program Cave and Mine Specialist        summer maternity colonies and
                                          during fall swarm/early hibernation     Little brown bats receive an oral WNS
Results from winter 2019-2020             at hibernacula.                         vaccine from USGS National Wildlife
hibernacula surveys in Wisconsin will                                             Health Center staff. Photo: Jennifer
help determine possible protections       Passive Integrated Transponder          Redell
for three bat species nationally.         (PIT) systems were installed at the
In spring 2020, the DNR submitted         primary bat entrances of two study      investigating movement and
bat data to the North American Bat        sites in Pierce County in September     transmission of Pd/WNS across the
Monitoring Program (NABAT) as part        2019 to monitor activity by research    midwest.
of a nationwide data request by           bats that were marked with a PIT tag.
the United States Fish and Wildlife       More than 300 little brown bats were    This ongoing project is providing
Service to help fill in data gaps on      vaccinated and distributed among        a unique look at sites before WNS
three sensitive bat species being         treatment groups at two hibernacula     arrived, during the infection, and
considered for federal protection:        in Pierce County. During our regular    after. In total, 20 sites were visited
little brown bat, eastern pipistrelle     winter surveys we opportunistically     one to two times in fall 2019 and
bat (aka tricolored bat) and northern     re-sighted and processed (scanned,      spring 2020. We provided landowner
long-eared bat. These species already     band read, swabbed, wing check)         access and field support when
receive state protection in Wisconsin,    some of these project bats. In          necessary. Samples from hibernacula
having been added to the state            addition to providing onsite support    environments as well as all four cave
threatened species list in 2011.          during research trips, local DNR        bat species were collected from fall
                                          staff changed batteries on the PIT      of 2019 and through spring of 2020,
Hibernacula data submitted to             tag systems to allow for continuous     ending just before state restrictions
NABAT came from 616 site visits to        reading of treatment animals to         were enacted due to the pandemic.
133 hibernacula in 29 counties. Sites     assess seasonal activity levels and
included beer caves, railroad tunnels,    survival.                                         Take A Virtual Tour Of
caves and mines surveyed between                                                               Kickapoo Caverns
2010-2020. In total, for the three cave   The field trials in early 2020          Finally, if you’re keen to explore
bat species across all survey years,      demonstrated the vaccines were          an underground space from the
1,045,029 bats were counted.              safe for bats, and at least one         comfort of home, join me on a virtual
                                          vaccine increased survival in males     tour of Kickapoo Caverns, one of
WNS Vaccine Trials Show Promise           and significantly reduced levels        Wisconsin’s longest cave systems
Since 2014, the Wisconsin Bat             of the fungus causing white-nose        and an important bat hibernaculum.
Program has worked with the United        syndrome. More trials began this fall   The online tour hosted by caverns
States Geological Service National        in Wisconsin to test specific vaccine   owner Mississippi Valley Conservancy
Wildlife Health Center, University        candidates.                             is titled “Home to Hibernating Bats”
of Wisconsin-Madison, Mississippi                                                 and is available in two parts on the
Valley Conservancy and Virginia Tech       Logistical Support Provided To WNS     conservancy’s Youtube channel. The
to develop and evaluate vaccines                    Transmission Study            tour covers general bat ecology,
to help bat populations recover,          In 2020 our program continued its       white-nose syndrome, how our
including undertaking the first           partnership with the University         program and partners study bats
vaccine trials in the wild for any        of California- Santa Cruz/Virginia      and the cave’s geology, history and
disease affecting bats. In the past       Tech white-nose syndrome project        importance as a bat hibernaculum.
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
8        Wisconsin Bat Program • 2021

          Acoustic Bat Monitoring Update
  Volunteers Take To The                 looked and felt very different this      importantly, safely) be conducted
                                         year. Nevertheless, once we figured      alone or within a family group. Or
   Water, Detect Mixed                   out how to safely monitor for bats in    could it be attributed to an amazing
     Results For Bats                    mid-June, mobile acoustic bat surveys    core of coordinators and volunteers
                                         began flooding in. In fact, despite      who would stop at nothing to collect
           By J. Paul White              missing the first two months of the      bat data? Both likely account for such
        DNR Mammal Ecologist,            bat monitoring season, looking at the    a strong outpouring of data amidst
          Bat Program Lead               numbers – 253 acoustic surveys in 48     very trying circumstances. A sincere
                                         (of 72) counties – one would not have    thank you from the Wisconsin Bat
         A Year Like No Other            known our volunteers were restricted     Program to everyone who participated
Unfortunately, due to....well, you       by a pandemic. Perhaps their survey      in the 2020 acoustic bat monitoring
know the rest of that sentence all       effort was a result of an outdoor        season!
too well. It’s no mystery why things     activity that could easily (and more

               2020                          2019
          150 participants              393 participants
            253 surveys                    376 surveys
            48 counties                    50 counties
       109 paddling surveys           113 paddling surveys
        100 driving surveys            135 driving surveys
        44 walking surveys            128 walking surveys
    70 surveys in Vilas County*    73 surveys in Vilas County
   *County with the most acoustic surveys

  Acoustic detector mounted on a kayak.
  Photo: J. Paul White

Sobering Results For Two Species But     catalogued. Unfortunately, not one of    and streams, a finding from the bat
   Better News For Little Brown Bats     the nearly 15,000 bat encounters was     diet study Amy Wray summarizes on
Volunteers, DNR staff and partners       classified as a northern long-eared      page 15 I think we can all agree that
like the United States Forest Service    bat and only six were labeled as calls   more little brown bats eating flies,
took part in the shortened 2020          of the eastern pipistrelle bat. The      midges and mosquitoes is a good
acoustic bat monitoring season. Most     acoustic silence is, regrettably, also   thing. The frequency of detection is
surveys (94%) were one- or two-          reflected in our winter hibernation      likely bolstered by that fact that 84%
person surveys and on average lasted     surveys, in which each year fewer bats   of water surveys detected little brown
one hour and 20 minutes. The most        of either species are observed or in     bats and there were more of such
surveyed areas in Wisconsin this year    some cases, not found at all.            surveys than either driving or walking
were aquatic waterways (109 surveys)                                              routes.
– thank you Vilas County! – while        Fortunately, it wasn’t all bad news.
100 surveys were driven and 44 were      For every three acoustic surveys         Big brown bats and hoary bats were
walking routes.                          completed, two detected a little         found on roughly 75% of all surveys
                                         brown bat, which is good news. Since     completed, making them the most
From these surveys, over 14,900 bat      little brown bats commonly forage on     frequently encountered species
calls were collected, analyzed and       aquatic insects found at rivers, lakes   followed by little brown bats (65.2%),
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
9        Wisconsin Bat Program • 2021

Hoary bat.
Photo: Heather Kaarakka

eastern red bats (67.2%) and silver-
haired bats (36.4%).

See page 10 for a map of most
commonly detected species.                  The sunset over Little Lake Butte Des Morts
                                            just before conducting a bat survey.
Eastern pipistrelles and evening bats       Photo: J. Paul White
were found only on a total of five
surveys and there were zero northern    nationwide data request by U.S. Fish        surveyors are active when many folks
long-eared bat encounters.              and Wildlife Service to help fill in data   are inside for the night, there are
                                        gaps on sensitive bat species being         opportunities to observe interesting
With the multitude of threats bats      considered for federal protection. The      nighttime behavior or rare wildlife.
continue to face from white-nose        species -- little brown bats, eastern       In some cases, we’ve passed along
syndrome to wind energy-related         pipistrelles and northern long-eared        observations to DNR species experts
mortality, the Wisconsin Bat Program    bats – are already on Wisconsin’s           that have helped confirm species in
will continue to collect acoustic bat   threatened species list. Acoustic           new locations or where they haven’t
data from this highly mobile and        data that fit the service’s request         been observed for many years, if not
secretive group of mammals to assess    came from acoustic bat driving              decades. Here are a few observations
Wisconsin’s bat population at the       transects and stationary sources.           surveyors turned in from 2020 routes:
local, state and regional level.        In total, the Wisconsin Bat Program         • Driving route – Central Lake
                                        submitted 32,482 acoustic files from            Michigan Coastal 1 (Shawano
            A Call For Data             mobile surveys spanning seven years             County) – “Saw a barred owl, two
In spring 2020 the Wisconsin Bat        (2013-2019) and 313,046 acoustic                porcupine, three raccoons, many
Program submitted acoustic bat data     files from five stationary long-term            deer. Heard whip-poor-wills in
to the North American Bat Monitoring    bat monitoring stations (2007-2017).            Navarino State Wildlife Area and
Program (NABAT) as part of a            These data were not only collected              eastern gray tree frogs.”
                                        by DNR staff but also federal partners      • Paddling route - Little Tamarack
                                        like the U.S. Forest Service, tribal            Flowage survey (Vilas County)-
                                        partners from the Bad River Band of             “What a beautiful evening for a
                                        Lake Superior Chippewa Indians and              bat survey! So lucky to have my
                                        volunteers.                                     daughter and son-in-law to share
                                                                                        the experience.”
                                             Notable Notes From This Year           • Walking route - Sanders Park
                                        We encourage you to report                      (Racine County) - “Nice evening,
                                        your supplemental observations                  but bits of rain near 3/4 mark
                                        whether they relate to bat activity,            - hence early quit. Had trouble
                                        the functionality of the detector               walking that far - this lockdown
                                        or other interesting notes. From                has eliminated staying in shape.
                                        birds, to amphibians, to mammals,               Or whatever excuse is needed.”
                                        to local weather conditions or
 Big brown bat.                         other “interesting” comments, we            Stay safe and best wishes for 2021.
 Photo: Dave Redell                     will happily accept all notes. Since
ECHOLOCATOR EC HO LOC ATOR - Thank You For Helping Us Through 2020 - The Wisconsin ...
10   Wisconsin Bat Program • 2021
11       Wisconsin Bat Program • 2021

Roost Monitoring Update

   Even A Global Pandemic Couldn’t
 Stop Bat Monitoring Volunteers From
       Surveying Bats This Year
        By Heather Kaarakka               bats were from sites that house both      which gives a little more evidence
     DNR Conservation Biologist,          little brown bats and big brown bats      that bat populations are possibly
    Bat Program Roost Monitoring          or it is still unknown which species      stabilizing after white-nose syndrome
             Coordinator                  uses the roost.                           (WNS). Some little brown bat roosts
                                                                                    even went from zero bats in 2019 to 10
Like most things this year, the           This year’s Great Wisconsin Bat Count     to 20 bats in 2020. It’s difficult to say
pandemic played a role in how             continued although the pre-volancy        whether this is evidence of increasing
summer bat roost monitoring worked        count – the count taken before pups       populations or whether bats are
in 2020. Social distancing and safer-     begin flying (volancy refers to flight)   still moving among roosts as we’ve
at-home directives meant volunteers       -- was delayed until mid-June. Roost      discovered that they do quite a bit.
could not travel to or gather at          monitors surveyed at 90 roosts in         We also know there’s no set number
several of our large little brown bat     June and 125 roosts in July. The first    of bats at a roost and bat counts can
roosts to count bats and delayed our      count in June aims to record adult        change dramatically even daily.
annual Great Wisconsin Bat Count.         colony sizes and the second count in
Bat monitoring volunteers are             July records numbers in colonies after    Little brown bats and eastern
resilient, however, and surveyors         pups start flying. These differences      pipistrelles continue to be the
still completed nearly 600 bat            in numbers before and after pups fly      hardest hit by white-nose syndrome
counts at 178 roost sites. Even more      can give us a sense of reproduction       at monitored bat houses and building
impressively, they monitored more         in colonies. We see increases in bat      roosts. While little brown bats are
roosts than ever, adding several          numbers at almost every roost site        starting to show some evidence of
new little brown bat roosts to our        (and in acoustics surveys too) after      colony stabilization and possibly even
database as well as 12 big brown bat      juvenile bats begin to fly. See our       recovery, eastern pipistrelles were not
roosts.                                   infographic below for this year’s         observed this year at two of the three
                                          numbers and read more about bat           summer roosts monitored. This year,
In 2020, volunteers counted a total       roost monitoring in the 2020 Annual       again, summer roost counts of these
of 12,844 bats, not so different from     Roost Monitoring Report.                  two bat species mirror low numbers
the 13,408 bats counted during 774                                                  recorded on acoustic surveys. We
surveys in 2019. Based on the highest        2020 Counts Add To Evidence Bat        will continue to watch these known
count from each site, volunteers and         Populations Are Stabilizing After      eastern pipistrelle roosts closely in
landowners counted 7,771 little brown             White-Nose Syndrome               the coming years and hope that we
bats, 4,792 big brown bats but only six   Like 2019, this year’s bat roost counts   see bats return.
eastern pipistrelles. The remaining       were similar to the previous year,
12       Wisconsin Bat Program • 2021

   Study Explores Linkage Between
 Roost Characteristics & Bat Declines
While we were not able to start our
                                            A little brown bat snug in a barn
project marking bats at persisting
                                            in Jefferson County in 2019.
colonies this year, we began a
                                            Photo: Heather Kaarakka
study looking at why there may be
differences in declines at little brown
bat roost sites. By using yearly colony
estimates collected since 2010 by
landowners and volunteers at 35
sites, we can investigate the change
in colony size year-to-year. From
these changes we can learn when the
biggest declines occurred and start
comparing the roosts using factors
such as age of the roost, how close it
is to permanent water and distance
to hibernation sites. This winter we’re
hoping to get an idea of whether
there are habitat and landscape
aspects that impact how big declines
have been and how quickly colony
sizes may stabilize after WNS.

           Thermal Imaging
           Project Heats Up
Another project we were able to           to continue another season of daily         We’re still analyzing footage, but at
pursue in 2020 used thermal cameras       counts at several little brown bat          one site, bat numbers and behavior
to record bat numbers and behaviors.      roost sites. We placed cameras later        appear similar to last year, which
Since these cameras are remote and        than we hoped due to the pandemic           provides more evidence some little
don’t require direct interaction with     but also left them later into the fall to   brown bat colonies may be stabilizing.
landowners or the bats, we were able      see colony dynamics in late summer.

  Thermal cameras allow
  surveyors to see bats in the
  dark using heat. The warm
  bats and their roost are
  orange and yellow while
  the cooler background is
  blue. Right: Three bats are
  emerging from a bat condo
  in Trempealeau County.
13       Wisconsin Bat Program • 2021

                      Thank You For Your
                    Dedication & Information
Even a global pandemic couldn’t         drives around with a microphone      and the impacts that threats like
stop bat monitoring volunteers          on their car to record bat calls.    white-nose syndrome are having
from surveying bats this year, and it   The information that hundreds of     on Wisconsin’s bats. Thank you to
reminds us how much the Wisconsin       volunteers have helped collect for   everyone who surveyed bats this
Bat Program has benefitted from the     over a decade have opened doors      year and at any point since 2008. The
dedication and hard work of everyone    to research that can help us learn   Wisconsin Bat Program would be very
who counts bats at roost sites or       more about bat biology and ecology   different without you.
14       Wisconsin Bat Program • 2021

              Wisconsin-Based Research
              Continues To Illuminate WNS
Studies with our research                   effects of research or census‐             with respect to how WNS
partners using data collected in            related visitation frequency               dynamics and impacts may differ
Wisconsin culminated in several             on populations. We found no                among bat species. Targets for
new publications over the past              evidence that more frequent visits         WNS research were highlighted.
months. These results are advancing         decreased population growth                This tool will be used to maximize
understanding of impacts of white-          rates for any of these species.            the likelihood of achieving bat
nose syndrome and informing how we          These results indicate that                conservation goals within the
might support bat populations during        visitation frequency (1–3 research         context and limitations of specific
recovery.                                   visits per year) had undetectable          real‐world scenarios.
• Results confirmed that bats are           impacts on bat population growth           Report: Identifying research needs
    most likely to spread Pd when           rates both with and without the            to inform white‐nose syndrome
    they are highly infectious, but         additional stress of an emerging           management decisions, as seen
    have reduced mobility and the           infectious disease.                        in Conservation Science and
    timing of Pd introduction has had       Report: Impact of censusing and            Practice.
    consequential effects for some          research on wildlife populations,      •   Diverse microbial skin
    bat communities.                        as seen in Conservation Science            assemblages, including fungal
    Report: Mobility and                    and Practice                               communities, may prevent
    infectiousness in the spatial       •   In our neighboring state of                pathogens (Pd) from colonizing
    spread of an emerging pathogen,         Michigan, several banded, male             a bat’s skin. Samples collected
    as seen in Journal of Animal            Little brown bats aged 18-25               from bats in Wisconsin were used
    Ecology (pre-print).                    years have been recaptured                 to determine that bat species
• Lower levels of Pd in caves               in a hibernaculum where WNS                with low skin fungal diversity and
    and mines consistently meant            likely has been present since              abundance were more susceptible
    delayed onset of WNS in bats,           2013–2014, indicating that these           to WNS than bat species with
    fewer and less severe infections,       old and apparently healthy males           higher fungal diversity and
    and reduced population impacts          are in their seventh season of             abundance (big brown bats).
    across regions. Extensive and           exposure to the disease. These             Report: Skin fungal assemblages
    persistent environmental                findings have been mirrored                of bats vary based on
    reservoirs led to early and             by several similar recaptures              susceptibility to white-nose
    widespread WNS presence and             at a hibernation site here in              syndrome, as seen in The ISME
    severe population declines.             Wisconsin. This gives us hope that         Journal.
    Continental differences in the          certain individual bats can live for   •   Instead of avoiding warm and
    persistence or decay of Pd in the       many years despite the presence            deadly underground sites where
    environment altered infection           of WNS in their hibernaculum.              the WNS fungus thrives, bats
    patterns in bats and influenced         Report: Exceptional Longevity              continue to use them year
    whether host populations were           in Little Brown Bats Still Occurs,         after year. Bats are mistakenly
    stable or experienced severe            despite Presence of White-nose             preferring sites where fungal
    declines from this disease.             Syndrome, as seen in the Journal           growth is high and therefore
    Report: Environmental reservoir         of Fish and Wildlife Management            their survival is low. This is one
    dynamics predict global infection   •   Using a cross-disciplinary                 of the first clear examples of
    patterns and population impacts         approach, diverse subject                  an infectious disease creating
    for the fungal disease white-nose       matter experts created an                  an “ecological trap” for wildlife.
    syndrome, as seen in PNAS.              influence diagram used to                  Report: Continued preference
• Out of concern that our own               identify uncertainties and                 for suboptimal habitat reduces
    research and monitoring visits          prioritize research needs for WNS          bat survival with white-nose
    could harm hibernating bat              management. Critical knowledge             syndrome, as seen in Nature
    populations, we quantified the          gaps were identified, particularly         Communications.
15      Wisconsin Bat Program • 2021

                   Diet Study Reveals Bats’
                  Importance To Ecosystem
                                                                                     Little Brown Bats’ Big Appetite
                                                                                     Mosquitoes & Ag Pests Beware

                                                                                    A single bat can eat the
                                                                                    equivalent of half its body
                                                                                    weight in insects every night.
                                                                                    Amy Wray, UW-Madison
                                                                                    PhD researcher, identified,
                                                                                    quantified, and analyzed what’s
                                                                                    on the menu for Wisconsin
                                                                                    bats and why that matters. She
                                                                                    • Bats consumed 17 distinct
                                                                                        types of mosquitoes,
                                                                                        including nine species
                                                                                        known to carry West Nile
                                                    Amy Wray, right, and field          virus.
                                                   technician Jamie Wang set        • Bats consumed 24 species of
                                                      up solar-powered traps            agricultural pests, including
                                                        in 2018 to capture the          black cutworm moths,
                                                 night-flying insects bats eat.         fruit tree leafroller moths,
                                                       Photo: Elaine Swanson            tarnished plant bugs and
                                                                                        spotted wing drosophila.
            By Amy Wray                  brown and big brown bat declines           • Little brown bats’ smaller
  University of Wisconsin-Madison        from white-nose syndrome.                      size makes them more
           PhD Researcher                                                               agile and better adapted
                                                   Different Bat Species                for capturing smaller prey.
A University of Wisconsin-Madison                   Eat Different Foods                 Sadly, these bat species are
study examining the diets of bats in     Overall, we found that little brown            one of the three species in
Wisconsin has revealed that different    and big brown bats eat different               Wisconsin most decimated
bat species target different insects     prey, with big brown bats eating               by white-nose syndrome, a
and highlighted the importance of        more beetles and caddisflies and               deadly disease of bats.
little brown bats to agriculture and     little brown bats eating more moths        • Declines in little brown bats
the nocturnal food web.                  and flies (especially certain types of         due to white-nose syndrome
                                         midges). These results were mostly             may lead to short-term
Over a 4-year period, we collected 560   consistent with previous studies on            increases in the abundance
guano samples to analyze bat diets       bat diets in other regions, except             of certain insect prey.
using molecular methods, captured        Wisconsin bats tended to consume
and identified 2,003,493 insects in      more insect prey typically associated
order to quantify changes in bat prey    with aquatic habitats. We also found     prey, further establishing their
communities, and recorded 6,245          that even though insect communities      sophistication as nocturnal predators.
nights of bat calls to understand        changed from week to week, bats
changes in bat activity. This study      tended to eat their favorite foods             Smaller Bat Species Suffer
also incorporated roost emergence        regardless of the abundance of other         Bigger Declines At Study Sites
counts from the Great Wisconsin Bat      options. These findings suggest that     Between 2015 and 2018, we
Count, with the goal of understanding    both little brown and big brown          unfortunately observed little brown
the ecological consequences of little    bats selectively hunt for particular     bat emergence counts decline
16       Wisconsin Bat Program • 2021

                                                                                   Guano samples collected for
                                                                                   analysis of bat diets using DNA. Big
                                                                                   brown bats have big brown poops
 Captured insects are sorted before                                                (left) while little brown bats have
 identification and counting by microscope.                                        little brown poops (right).
 Photo: Amy Wray                                                                   Photo: Amy Wray

by about 95% at our study sites.         see a statistically meaningful decline
Similarly, we detected a nearly 80%      in low-frequency bat activity, which
decline in high-frequency acoustic       corresponds to big brown bats but
activity around the study sites,         includes other species such as hoary
which corresponds to little brown        bats and silver-haired bats.
bats but also includes tricolored
bats, northern long-eared bats and         Declines In Little Brown Bats May
eastern red bats. Based on previous       Have A Bigger Impact On Food Web
studies and hibernacula surveys,         From our insect trapping surveys,
these declines in little brown bats      we found that between 2015 and
are largely attributable to white-nose   2018, the total abundance of insects      A Cecropia moth captured in a
syndrome. In comparison, we found        declined by nearly 50% at our             black-light trap was not found in
that big brown bat emergence counts      study sites. The reason for these         the diets of Wisconsin bats.
declined by 40%, but this trend was      declines is not totally clear and         Photo: Amy Wray
mainly driven by a decline in a single   could represent either a natural
large roost which may have been          fluctuation or a declining trend         after declines from white-nose
related to movement rather than to       warranting further investigation.        syndrome were observed among
white-nose syndrome. We also did not     However, our study was mainly set        little brown bats in Wisconsin. Since
                                         up to address how bat population         Chironomidae are one of the favored
                                         declines influenced the abundance        prey items of little brown bats, these
                                         of insects, which we investigated        results suggest that declines in little
                                         by setting up insect traps near bat      brown bats may lead to a local-scale
                                         roosts and at paired “control” sites     increase in the abundance of these
                                         further away with lower bat activity.    midges. While many studies have
                                                                                  shown other bat species controlling
                                         When comparing these different           insect abundance, including
                                         experimental treatments, we found        suppressing agricultural pests, our
                                         that most insect groups displayed        study suggests that little brown bats
                                         similar patterns in abundance at         may have an impact on other types of
                                         sites near bat roosts and at sites       insects too.
                                         far from bat roosts. As a notable
                                         exception, we saw an increase in            Little Brown Bats Eat Dozens Of
                                         the abundance of Chironomidae,                Species Of Agricultural Pests
                                         a family of midges, at little brown      Since ecosystem services provided
                                         bat roost sites compared to control      by bats are always important to
 A black-light trap full of
                                         sites. These trends were observed        quantify, we also looked at how many
 Chironomid midges.
                                         in 2016 and 2017, the first two years    agricultural pests were present in
 Photo: Amy Wray
17       Wisconsin Bat Program • 2021

bat diets. At least one agricultural      some resistance to white-nose           as easily. Cumulatively, our studies
pest species was detected in 45% of       syndrome, could potentially fill        provide more evidence that little
little brown bat guano samples and in     the ecological role of little brown     brown bats not only influence prey
34% of big brown bat guano samples.       bats as predators. We did this by       communities, but also appear to have
Interestingly, before declines from       comparing diet composition before       a unique role as insect predators in
white-nose syndrome, little brown         and after declines from white-nose      the nocturnal food web. In light of
bat guano samples contained more          syndrome, specifically with the goal    bat population declines from white-
agricultural pests (53% of samples        of quantifying whether big brown        nose syndrome and other factors,
had at least one pest species) in         bats would select more of the prey      continuing to protect and support
comparison to guano samples               previously consumed by little brown     bats therefore remains important
collected after declines from white-      bats. We found that following little    from an ecosystem-wide perspective.
nose syndrome (16% of samples             brown bat declines, there was little
had at least one pest species).           change in the diet composition of       These studies would not have been
This change in little brown bat diet      big brown bats, and the amount of       possible without the support of
composition might indicate that           dietary overlap between the two bat     the DNR, the many volunteers who
larger populations of bats are more       species also did not increase over      contributed to emergence counts,
likely to consume a higher diversity of   time. While these species may appear    and the landowners who allowed
insects overall, and therefore may be     similar at first glance, little brown   sampling of bat guano and insects
more likely to eat a greater number of    and big brown bats are ecologically     on their property. Study sites also
agricultural pests.                       distinct as predators. Little brown     included Governor Dodge State
                                          bats, with their smaller body size,     Park, Yellowstone Lake State Park
    Little Brown Bats, Hard Hit By        are more agile and better adapted       and Silverwood County Park, and
     WNS, Have A Unique Role As           for capturing smaller prey. As such,    we are most appreciative of their
         Predators In Food Web            big brown bats may be somewhat          participation.
Finally, we assessed whether big          constrained by their larger body size
brown bats, which demonstrate             and cannot capture smaller insects
18       Wisconsin Bat Program • 2021

     Bats With White-Nose Syndrome
    Prefer Suboptimal Habitats Despite
            The Consequences
            Excerpted from
      Virginia Tech News Sources

Since 2006, a fungal disease called
white-nose syndrome has caused
sharp declines in bat populations
across the eastern United States.
The fungus that causes the disease,
Pseudogymnoascus destructans (Pd),
thrives in subterranean habitats
where bats hibernate during the
winter months.

Bats roosting in the warmest sites
have been hit particularly hard, since
more fungus grows on their skin,
and they are more likely to die from
white-nose syndrome, according to a
new study by researchers at Virginia

But instead of avoiding these warm
and deadly sites, bats continue to use
them year after year. The reason? Bats
are mistakenly preferring sites where
fungal growth is high and therefore
their survival is low. This is one of the
first clear examples of an infectious
disease creating an “ecological trap”
for wildlife.

Dr. Kate Langwig and Dr. Joseph Hoyt,        Joseph Hoyt of Virginia Tech gently swabs the forearm of a hibernating Big brown bat in
both assistant professors from the           2017 as part of a multi-year effort to understand the impacts of WNS.
Department of Biological Sciences            Photo: Jennifer Redell
in the College of Science, have been
studying little brown bat (Myotis           “We see that there is a shift across             still choosing to roost in warmer
lucifugus) populations in Michigan          the regional bat population over                 sites, even though colder sites
and Wisconsin since 2012, before the        time,” said Skylar Hopkins, a previous           are available. But on average, bat
fungus first reached those states.          postdoctoral scholar at Virginia Tech            roosting temperatures have declined,
This long-term study was the perfect        and now assistant professor at North             because the colder-roosting bats
opportunity to see if bats alter their      Carolina State University.                       have had higher survival rates.”
preferences across hibernacula, or
hibernation sites, in response to the       “When we look at the population                  Now that they know that bats are
invasion of white-nose syndrome.            post-invasion, we see that more                  preferring high mortality sites,
                                            than 50 percent of the bats are                  Hopkins hopes that their data can
19       Wisconsin Bat Program • 2021

be used to think about which sites         about the warm sites that are acting
researchers and conservationists           as ecological traps and whether we
need to prioritize for conservation        should be trying to manage those
and how to conserve them.                  sites in a different way. Maybe there
                                           are interventions that should be done
“Because we know that bats are doing       at those si tes to prevent most of the
better in the cold sites, the cold sites   population from going there each
may be good ones for us to conserve,”      year and having these big mortality
said Hopkins. “We can also think more      events.”

                                                                                    Doctors Langwig, Hoyt and Kilpat-
                                                                                    rick collect samples of the WNS
                                                                                    fungus from hibernating Big brown
                                                                                    bats in Wisconsin in 2015.
                                                                                    Photo: Jennifer Redell
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