The Battle For Bats
are in serious decline nearly everywhere. Worldwide, there
are almost a thousand different kinds of bats which comprise
nearly 1/4 of all mammal species. Of the 43 species living
in the U.S. and Canada, nearly 40 percent are endangered or
are candidates for such status. The biology and ecology of
bats is not well understood. Their nocturnal behavior, inaccesible
breeding and roosting sites, and migratory behavior have made
them difficult to study. As a result, we know little of bat
ecology or management needs on public lands. Despite a lack
of knowledge, we do know that bats often use trees, cliffs,
caves, human dwellings, natural waters and water developments,
bridges and mine shafts in a variety of habitats. There are
clearly opportunities to begin specific management actions
to protect or enhance this diverse and threatened group of
One method that the Forest Service is using to protect critical
bat habitats is the installation of iron grates over abandoned
mine entrances. These "bat-gates" serve two primary
purposes: they protect the public from stumbling into a mine
that might be dangerous, as well as protecting habitat allowing
passage for bats. In the past, many abandoned mines have been
filled in with earth, often a costly proposition that is deadly
for bats. Maintaining the mine for bats provides a win-win
situation that is both simple and cost-effective. With approximately
25,000 abandoned mines on Forest Service lands and an estimated
200,000 across the U.S., there is great potential to make
a significant positive impact on bat populations through this
method of protection.
Bat Conservation International and USDA Forest Service Sign MOU
Dr. Merlin Tuttle, President/Founder Bat Conservation International, Inc. and Deputy Chief Joel Holtrop recently signed a new Service-Wide Memorandum of Understanding (MOU, enclosure). This MOU recognizes our longstanding partnership and mutual interest in the conservation and management of bats, their habitat and associated ecosystems, and our common desire to expand our cooperative work.
Bat Conservation International’s (BCI) mission is to protect and restore bats and their habitats worldwide by helping people understand and value bats as essential components of ecosystems. BCI advocates protecting critical bat habitats, advancing scientific knowledge about bats and their conservation needs, and facilitating management approaches that help both bats and people.
The Forest Service has a proven track record of working in collaboration with BCI, focusing especially on helping employees to understand and value bats as essential allies in managing habitats, and advancing scientific knowledge about bats, conservation needs, and ecosystems through continuing education, training, and cooperative research. By managing for bats and their habitats, the Forest Service contributes to conservation of the nation’s biodiversity, creating a healthier environment for both wildlife and people.
Investing in partnerships takes time, effort and energybut it is worth it, and is in the Forest Service’s and the public’s interest. Partnerships such as these allow the Forest Service to effectively do more of the important conservation work that benefits the public’s resources.
Thanks to all who contributed to preparation and review of this MOU!
MOU with BCI and FS 41.4 KB PDF
Letter Announcing BCI-FS MOU 25 KB PDF
Partnership Opportunities with BCI 47 KB PDF
Big Brown Bat
Taken by Dennis Krusac, USFS
Save the Planet with BATS - 2008 Bat Blitz on the Bankhead NF
An excellent piece, featuring our own (!) Dennis Krusac, Region 8 biologist, is featured in this segment. Channel 42 in Birmingham, Alabama is covering the 2008 Bat Blitz in the Bankhead National Forest. There are a few errors, like there are in any news story, but it is a good story. The film crew from Discovering Alabama was at the blitz all 4 days and they are planning an entire show on bats. Don not know when the 'Discovering Alabama' show will be available, but it should be very good.
Links to Channel 42:
Abandoned Mines - Bat Barracks
Abandoned mines have become key year-round resources for
bats. Mines seem to be most important for rearing young in
summer, for hibernating in winter, and for use as temporary
rest stops during migration. Throughout the United States,
human disturbance of caves, cave commercialization, deforestation,
and urban and agricultural development have forced many bats
from their traditional roosts in search of new homes. Old
mines are often the only suitable temperature-controlled shelters
left midway between a bat's summer and winter roosts; without
these protected resting places, many species' migratory mortality
could greatly increase. Over the past 100 years or more, displaced
bats have gradually moved into many mines. In more than 6,000
mines surveyed by researchers in Arizona, California, Colorado,
and New Mexico, 30 percent to 70 percent in each state showed
signs of use by bats. An average of 10 percent contained important
colonies. From the Great Lakes Region eastward in the U.S.,
up to 70 percent of subsurface mines may be used by large
bat populations. Bats, due to their colonial nature, are especially
vulnerable during hibernation both to vandals, and to rapid
mine closures. The largest recorded hibernating population
of western big-eared bats was recently destroyed in a New
Mexico mine shaft where vandals had set old timber on fire.
In New Jersey, the state's largest population of hibernating
bats was inadvertently trapped in the Hibernia Mine when it
was capped. Had state biologists not convinced state authorities
to reopen the entrance immediately, these bats would have
perished. Likewise, the Canoe Creek State Park limestone mine
in Pennsylvania was reopened in the nick of time to save its
bats and now shelters the largest bat hibernating population
in the state. Clearly, the difference that protecting and
stabilizing just one mine shaft can make is tremendous.
Bats Are A Big Deal
Bats are a primary predator of vast numbers of insect pests
that cost farmers and foresters billions of dollars annually.
Bats also pollinate flowers and disperse the seeds that make
the rain forests grow and the deserts bloom. Wherever bats
are found, they are critical elements in nature's delicate
web of life.
How YOU can help bats
- Contact your State Department of Natural
Resources about area mines and bat gaiting.
- Join Bat
- Ask your local Forest Service office about
- Ask your local Forest Service office or
Bat Conservation International about them hosting the "Bat
Cave" interactive educational unit at your local school(s).
(The "Bat Cave" is still under construction by
the Forest Service. Once the parts and pieces are assembled
into a traveling unit it will be shipped to Bat Conservation
International for review, improvement and management.)
- Build or buy a bat house and put it up in
your yard. Contact Bat
Conservation International about optimal placement.
- Help your neighbors learn about bats and
their benificial role in nature.
- Don't trap bats in your attic. Wait for
the bats to leave at night to go feeding and then close
up the holes in your attic. Contact Bat
Conservation International for further information.
- Read books about bats. Visit your public
library or other bat web sites.
the Experts at Scientific American
You can also find locations for viewing wildlife, plants and fish through our NatureWatch website (www.fs.fed.us/outdoors/naturewatch/where-to-go.php).
(borrowed from Scientific
the Experts") How do bats echolocate and how are
they adapted to this activity?
Alain Van Ryckegham, a professor at the School of Natural
Resources at Sir Sandford Fleming College in Lindsay, Ontario,
Canada, offers this explanation: Bats are a fascinating group
of animals. They are one of the few mammals that can use sound
to navigate--a trick called echolocation. Of the some 900
species of bats, more than half rely on echolocation to detect
obstacles in flight, find their way into roosts and forage
Echolocation--the active use of sonar (Sound Navigation
AndRanging) along with special morphological (physical features)
and physiological adaptations--allows bats to "see"
with sound. Most bats produce echolocation sounds by contracting
their larynx (voice box). A few species, though, click their
tongues. These sounds are generally emitted through the mouth,
but Horseshoe bats (Rhinolophidae) and Old World leaf-nosed
bats (Hipposideridae) emit their echolocation calls through
their nostrils: there they have basal fleshy horseshoe or
leaf-like structures that are well-adapted to function as
Echolocation calls are usually ultrasonic--ranging
in frequency from 20 to 200 kilohertz (kHz), whereas human
hearing normally tops out at around 20 kHz. Even so, we can
hear echolocation clicks from some bats, such as the Spotted
bat (Euderma maculatum). These noises resemble the sounds
made by hitting two round pebbles together. In general, echolocation
calls are characterized by their frequency; their intensity
in decibels (dB); and their duration in milliseconds (ms).
In terms of pitch, bats produce echolocation calls with both
constant frequencies (CF calls) and varying frequencies that
are frequently modulated (FM calls). Most bats produce a complicated
sequence of calls, combining CF and FM components. Although
low frequency sound travels further than high-frequency sound,
calls at higher frequencies give the bats more detailed information--such
as size, range, position, speed and direction of a prey's
flight. Thus, these sounds are used more often.
In terms of loudness, bats emit calls as low as 50 dB and
as high as 120 dB, which is louder than a smoke detector 10
centimeters from your ear. That's not just loud, but damaging
to human hearing. The Little brown bat (Myotis lucifugus)
can emit such an intense sound. The good news is that because
this call has an ultrasonic frequency, we are unable to hear
it. The ears and brain cells in bats are especially tuned
to the frequencies of the sounds they emit and the echoes
that result. A concentration of receptor cells in their inner
ear makes bats extremely sensitive to frequency changes: Some
Horseshoe bats can detect differences as slight as .000l Khz.
For bats to listen to the echoes of their original emissions
and not be temporarily deafened by the intensity of their
own calls, the middle ear muscle (called the stapedius) contracts
to separate the three bones there--the malleus, incus and
stapes, or hammer, anvil and stirrup--and reduce the hearing
sensitivity. This contraction occurs about 6 ms before the
larynx muscles (called the crycothyroid) begin to contract.
The middle ear muscle relaxes 2 to 8 ms later. At this point,
the ear is ready to receive the echo of an insect one meter
away, which takes only 6 ms.
The external structure of bats' ears also plays an important
role in receiving echoes. The large variation in sizes, shapes,
folds and wrinkles are thought to aid in the reception and
funneling of echoes and sounds emitted from prey. Echolocation
is a highly technical and interesting tactic. To truly understand
the concepts and complexity of this subject is to begin to
understand the amazing nature of these animals.
Library - University of New Mexico Bat
lab, the bat ecology and bioacoustics lab - University
of Bristol Adopt
a Bat - Bat Conservation International