Bats in our Midst – KQED QUEST


A KQED HD production People are frightened of bats because
they fly. People think they get in your hair. They purposely fly in your hair People want to know: Is it true? Do they
actually bite people? Bats have been misunderstood and
feared for centuries, but for the Northern California scientists and
volunteers who work with them everyday the very things that make these animals
scary also make them compelling. They fly and there’s no other group of mammals
that have powered flight. Around the world bats are important pollinators of
crops and other plants like cactus, but in California, they’re voracious insect
eaters that help control pests. I think they make an enormous
contribution when you consider that a lactating female may eat as much as her
own weight every night in the summer and here in the central valley you have huge
numbers of mexican free-tailed bats as a pest control service. Bat researchers
Dave Johnston and Winston Lancaster have been studying the mexican
free-tailed bats that live under a bridge 20 miles south of Sacramento. In
the summer, they’ve counted as many as 22,000
bats nestled in the wooden beams under the bridge’s third of a mile span. Now the
bats are in these tiny little crevices. They like the narrow space. That’s really
quite comfortable for them because they’re protected from predators. Today, Lancaster and Johnston are out with some
of their students from San Jose State University and Cal State Sacramento to
find out how many bats live under the bridge during the winter. About six right there. Dr. Lancaster and I would like to learn
more about the movement between the Central Valley and the Central
California coast. We’d like to know what the winter
population is presumably will be much fewer number of animals, those animals
that didn’t migrate. They’re cool you know. People think of them as rodents, but
they’re actually much more closely related to primates than they are to
rodents, and they’re really social and you know they’re fuzzy and cute. Under the
bridge Lancaster attempts to record some of the
bats’ calls. Bats use sound to orient in space. It’s a process called echolocation.
The animal makes a sound of some kind and waits for the echo to come back from
object in its pass. There’s a search phase of echolocation in which the animal is just
flying and making the sound looking for insects. Bats increase the rate of
repetition until they’re very close to the object, very very short calls and this is the last approach. While a human adult can only hear frequencies of up to 12
kilohertz, bats emit calls that are 20 kilohertz
and above. That’s why Lancaster needs a bat
detector to translate the high-frequency bat calls into sounds that humans can
hear. But when the bats are resting there aren’t any calls to record. We could be
hearing anything like I say us walking around wind noise the animals are moving a
little bit but there’s so little activity right now that I don’t expect
to hear a lot of echolocated vocalization or even social vocalization. You heard some before. I heard a few
social calls which are audible to us. You’ll hear the squeaky sound that’s
what that is. It’s “hello, how are you?” It’s “get out of my way.” It’s all those things, so this is a very
social species. With 1200 species of bats living around the world, bats are the
second most numerous group of mammals, after rodents. Some 25 species of bats are found in
California. We have some absolutely beautiful bats in California. The western
red bat, absolutely gorgeous color, and another is the spotted bat, which is
mostly all black, huge ears and three bright white splotches on it. Bats
are really beautiful because they have tri-colored hairs ofbrown black and white,
and they have relatively large eyes. So these are very very attractive
animals. So we’ve covered about ten or fifteen percent of the bridge so far, and
in that span I’ve counted about 2,500. And that’s actually more than I had
anticipated. At the end of the day, the researchers had counted almost 16,000
bats under the bridge many more than they expected. Their finding suggests that a group of
bats lives under the bridge year-round. You know, I thought that this would have
many fewer knowing that many of the Central Valley bats, the Mexican
Free-Tailed bats go into the Bay Area. The high numbers also reconfirmed that
the bridge remains one of the most important roosting places for Mexican
Free-Tailed bats in the Central Valley. This isn’t a coincidence. When Sacramento
and San Joaquin Counties rebuild the bridge in 2004, they worked to replace the
bat habit provided by the old wooden bridge. The Redwood boxes that were built
into the new bridge’s concrete have become a successful alternative. The
thermal dynamic qualities of that bridge, the concrete, heating up during the day
providing an optimal temperature to raising babies. So it’s definitely a
success story. But while some California bats, like the Mexican Free-Tailed, have
benefited from urbanization, other species have seen their numbers decline. They’re probably about 16 species of
bats in the Bay Area, and what we’re learning is that more and more of these
species are more sensitive to urbanization than I think we previously
thought. The Townsend big-eared bat, the pallid bat, are
probably the most sensitive. The long-eared myotis, we had thought that
that was probably doing reasonably well. It’s usually found in a number of for us
but we’re finding that we’re not seeing many recent records. But certainly
habitat fragmentation and habitat loss arw probably the big suspects. And even
the bats that do make a comfortable living under bridges and inside
buildings are under threat. When bats and humans come into close contact, the bats
often end up needing help from people like Francis Zitano. I am a pathologist
assistant at Kaiser South Sacramento hospital by day and at night I’m a bat rehabber. When I started looking for a house I figured I needed at least a three
bedroom, so that I can have a room for the bats. I’m permitted by the Department
Fish and Game and they are allowing me to take these animals in that are injured
or orphaned, and basically rehabilitate them, nurse them back to health and
re-release them into the wild. There we go. And there are five right now that are
waiting to be released when the weather gets better. (You better chew it). A lot of
calls are from people who have a bad in their house sometimes or somehow
they found it in their garden and it’s on the ground. Zitano and fellow bat
rehabilitator Corky Quirk nurse the backs back to help with worms for the
adults and warm smoothies for the young or injured. And they provide them
with pieces of cloth to hide behind. This one here is a Mexican Freetail. This
little girl is non-releasable at least for now because she’s having this
problem with her feet, where we I can’t tell if it’s an infection or something
but she seems to be losing some of her toes. Now this is a little brown bat and
he has a dislocated shoulder. My thought is possibly a cat jumped and
caught the bat well he was flying. Bats in California face a greater threat than
common predators. A fungal disease has killed more than 1 million bats in the
eastern United States since it was introduced to New York state in 2006,
likely from Europe. Infected bats appear to have frost on their snouts and chins.
The so-called white nose syndrome affects bats hibernating in caves
causing them to starve to death. They are constantly itching, irritated and they
may not be able to keep their fat reserves because their metabolism is at
a fairly high rate through the winter. And that may be why they’re emaciated
when they come out sometime in the early spring. Efforts to treat the disease have
failed. By 2011 the fungus had been confirmed in Indiana and bat scientists
expect it to reach California. Our bats typically do not go into the deep
hibernation when this fungus does its worst effects, so that’s a wild card out
there and we just don’t know how it’s going to affect our bats. Come on sweetie. It’s a really good feeling to know
that you’ve nursed it back and it’s okay and then you let it go. And there are a couple more things Zitano would like you to know about bats.
Bats don’t get in your hair unless you have a big hairdo. There’s only three species out of the
1200 in the world to drink blood and they’re all in Mexico, South America, or
Central America. And don’t worry, even those bats rarely bite people.

6 thoughts on “Bats in our Midst – KQED QUEST

  1. Rescue Australia has volunteers that care for bats that most often get caught in barbed wire, which can easily kill them as they struggle once caught. these bats appear to be affectionate, like mammals will respond to us humans. while growing up in the blue mountains of pennsylvania, the best time of day was when the bats started to come out, and how quickly they could zoom around you to avoid you. they have a beautiful wing span. Great video!

  2. quite a good and informative vid!! also .. just so anyone who might read this will know, the disease white noes is still (2013, fall) killing bats in the US.

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