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Bats
are one of the most interesting and unique mammals in the
world. There are over 1,000 different species of bats
worldwide and make up about a quarter of all mammal
species. They are important pollinators of such plants as
mango, banana, and cashews. Fruit-eating bats are very
important in the rain forest. They spread over half of the
initial seeds in a cleared rain forest. Finally, in our own
backyards, bats are the primary predators of night-flying
insects.
Bat Walks During the Day
Most bats hide from predators during the day while they
sleep, and thus can be very difficult to locate. Point out
places that bats might live and discuss some of these
aspects:
Some bats are solitary (live alone) and use camouflage to
keep them safe. This disguise usually takes the form of
blending in with the color of the tree, for example the
hoary bat often roosts in evergreen trees and uses its
brown, white, and yellow coloration to hang unnoticed.
Other solitary bats, like the red bat, hang in maple trees
from one foot, curl up in a ball, and pull their furry tail
membrane over their head to look like a leaf. Bats that
live in colonies (a group of bats) may live in a barn,
house, dead or dying tree, rock crevice, cave, cavern, or
in expansion joints beneath a bridge.
When looking around the city for bats, point out church
bell towers, shutters on houses, attic vents, on the
underside of bridges, and cracks in buildings. Bats will
usually be up high, in a warm, dry, dark location where
they await dusk. When looking for bats in a natural
setting, point out any dead or dying trees (bats often live
in dead trees, especially those with loose and peeling bark
and any cavities), live trees (especially evergreen, maple,
and sycamore trees), rock crevices, caves, shrubs, and
holes in cacti. During fall and winter, some bats have been
known to sleep under fallen leaves on the ground for
warmth.
Bat Walks at Dusk
If you are going to take a walk at night, make sure you are
familiar with the area and inform the participants of any
potential hazards. Consider limiting the size of the group
to ensure a pleasant experience. If there is a good
possibility of seeing bats up close, ensure that everyone
knows not to touch any bat. Bats are timid creatures, but
will bite in self-defense. Prior to the night walk,
recommend that the attendees wear suitably warm and
weatherproof clothing and shoes, and make sure to bring a
flashlight (red filter if available) and bug spray. Arrive
just prior to sunset and be on the lookout for bats flying
about 15 minutes after the sun goes down. The best time to
see bats is on a warm summer night when there a lots of
flying insects. In the Canada and northern United States,
bats hibernate (sleep through the winter) when the
temperatures go below freezing. Bats can be seen year round
in southern parts of the United States and into Mexico.
Dusk is the best time to look for bats because it’s
not yet too dark to see, but dark enough for bats to leave
their roosts. In the city, look for bats hunting around
lights on streets, playgrounds, football or baseball
stadiums, or parking lots. In natural settings, look for
bats near open water such as lakes, rivers, and ponds.
Stand so the water is between you and the sunset. The lake
will reflect the sky and light up the bats. Other areas to
see bats flying around are in fields, wetlands, prairies,
and at the edge of woods and forests. If you are lucky
enough to live near an existing colony, you can go at dusk
with a blanket and video camera to watch the emergence.
Some of the best places to find large numbers of bats are
caves, caverns, mines, bridges, barns, and bat houses.
Often, simply find swarms of insects and bats will soon be
there.
If you own or can borrow a bat detector, it is by far the
best way to tell if bats are flying in the area. Bat
detectors pick up bat echolocation calls as the bats fly
around foraging for insects. The microphone inside the bat
detector is capable of detecting high frequency sounds that
a human can’t hear. The detector then converts the
calls into a sound that we do hear.
Spotting a Bat
Record the time, place, and location of the discovery. What
is the bat doing, how is it flying, are other bats flying
in the area, how does it catch its food? Keep a journal of
your bat observations. You may also want to try to take a
picture, video, or audio recording. Make sure not to shine
a flashlight directly at the bat as it is flying. It may
change its foraging behavior or be easy prey for predators.
Be on the lookout for bat predators. Hawks, owls, and
snakes are a few animals that prey on bats. Birds of prey
can often been seen in the sky or on a branch waiting to
swoop down and grab a bat. Other known predators include
raccoons, opossums, and cats.
Make sure it is a bat and not a bird seen flying. Some
birds, like swallows and martins, have a similar silhouette
as bats and will be out at twilight hunting for insects.
One thing to know is that birds usually glide between
flapping, with wings close to their bodies. Bats rarely
glide and if they do, they usually have their wings
extended during flight. Also, birds usually fly in a
smooth, straight direction. Bats generally have erratic,
swooping flight. In addition, see if the animal is going
into a roost or coming out of a roost at dusk. Birds will
be heading in at sunset and bats will be emerging. Finally,
most bats in the North America are much smaller than their
nocturnal bird counterparts such as nighthawks and
owls.
Bat Walks with a Naturalist
Check with your local nature center, museum, zoo, or other
educational institution to see if a bat expert would be
willing to lead a bat walk. People who study bats often
carry bat detectors that translate bat echolocation (sonar)
into sounds humans can hear.
For More Information
You may find it helpful to pick up a copy of the
“Stokes Beginner’s Guide to Bats.”
This first of its kind field guide to bats of the United
States and Canada provides information about individual
species. Specifics about roosting, flight, migration and
more can be found in this book. In addition, after you go
on several bat walks, you may want to build or purchase
your own bat
detector.
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