Bats

Fall Can be a Batty Time for Schools

By Marcia Anderson

Just as children around the nation are back in school in the early fall, so are bats. Autumn is the time when many North American bats are beginning their trek south to overwinter in Mexico and Central America. Many schools are located along bat migration routes, so every fall, bats attempt to use them as rest stops.

Image: National Park Service

Image: National Park Service

Bats are essential to maintaining healthy ecosystems and economies. Some bats are primary pollinators of fruits and other produce. They spend their nights eating pests — mosquitoes, moths, as well as termites, ants and roaches in flight. A single Mexican freetail bat or little brown bat can eat 3,000 mosquito-sized insects per night. Their prey is easily found in open grasslands, parks, and school yards where insects are abundant. During the day, bats prefer to roost in tight crevices such as cracks in rocks, under exfoliating tree bark, and in awnings of buildings. Bats can enter buildings through openings as small as one-half inch in diameter.

One city’s high school experienced an annual bat problem. The building was over 100 years old, and every fall over 3,000 bats would spend time in the halls, classrooms, kitchen, and, primarily, the auditorium. The bats would fly in at dawn and exit at dusk at several sites scattered across the building. The custodians would go to work at 5 a.m., running nets through the school to capture the bats and release them outdoors. They would catch as many as they could before the start of the school day.

Then in 2005, the district began implementing an Integrated Pest Management (IPM) program. As the program got underway, the facilities management team soon began to understand how the bats were entering the building. As with preventing other pests that enter schools, exclusion was part of the IPM process that needed to be implemented. An 80-foot lift allowed staff to get high enough to seal the openings where the bats were entering.

2.Little brown bat Image: Marvin Moriarty, US Fish and Wildlife Service

Little brown bat Image: Marvin Moriarty, US Fish and Wildlife Service

Over the next three years, there was a significant decrease in the number of bats entering the school. By 2010, only one or two bats would find their way into the building when someone on the 3rd or 4th floor would accidently leave a window open. The good news for the bats was that the district had the foresight to place bat houses on the roof of the school so the bats would have a place to rest, undisturbed, on their long journey south.

A related problem the school had to deal with was the bat guano deposited in the attic spaces above classrooms. There are health hazards associated with bat guano, such as Histoplasma capsulatum, a fungus which, if inhaled, can develop into a serious respiratory disease. Guano also needs to be removed from interior structures to avoid attracting other pests such as cockroaches and flies. A professional hazardous waste cleanup company was hired to remove the bat guano.

In another part of the country, a school had hundreds of bats spend an entire season adjacent to their gymnasium. The bats found a perfect roosting space between the gutter and the building that ran for 500 linear feet. The void was about four inches high and ¾ inches wide, in a very high location, and inaccessible to predators – a perfect spot for bats. The local health department shut down the gym. The guano that collected on the ground below the bats had to be swept up daily. Some, however, fell inside the gym wall void. The facilities staff applied an enzyme inside of the wall void to neutralize any pathogens in the guano. To solve the problem, the school removed the gutter, installed flashing, and then reinstalled the gutter. This bat incident cost the district over $250,000.

Yet another school had an overhang 30 feet off of the ground that the bats loved. To keep them from roosting, the facilities staff filled the voids, added metal panels, and sealed the seams.

Got bats in your school? Don’t panic. They’re rarely aggressive. Do warn students not to pet, catch, comfort, kick, or shoo them away, as some bats carry rabies. Teach them to stay back and notify a teacher or staff member.

Exclusion is an essential step in IPM. Close all potential bat entry points using sealant, weather stripping, flashing, or heavy-duty ¼-inch hardware cloth. Identify bat entry points by inspecting along roof lines and under gutters for rub marks – stains left by the oils and dirt rubbing off the bats’ hair. Also look on the ground for guano.

Before taking action, know the bat species involved. A few bats are federally protected, so it is important to comply with the law. There may be more than one bat species sharing a roost. Identification can also help if the district is considering building alternative housing for the bats. Each bat house should be appropriate for the species, large enough to hold several hundred bats, and placed away from students. Not all commercially available bat houses are suitable for North American bats. Bat Conservation International provides information on how to build, buy, and install a bat house. There are also free plans for bat houses available online. Install new bat houses a few weeks prior to the actual bat exclusion, to allow them time to find the new shelter.

Lastly, Texas A&M University provides good information on bat control in schools.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Management of Much Maligned, Often Misunderstood Bats

By Marcia Anderson

During summer evenings in Maine, I often sit outside and watch the bats flying to and fro, devouring insects near the edge of a lake. Bats have a reputation for being spooky or even dangerous, but they are some of the most beneficial animals to people. Bats are misunderstood and needlessly feared. Bats actually do humans a great service, as each one can consume hundreds of crop-destroying insects and other pests every night.

Bats do not encounter people by choice and very few bats consume blood. Of the more than 1,100 bat species worldwide, only three feed on blood and none of those live in the United States.

New England is home to many species of bats including the big brown, little brown, red, hoary, batatnightEastern small-footed myotis, and Indiana bat. A single little brown bat can eat 3,000 mosquito-sized insects a night. Most North American bats have small teeth for eating insects including corn earworms, cucumber beetles, leafhoppers, stink bugs, mosquitoes, moths, termites, ants and cockroaches.

Bats are essential to maintaining healthy ecosystems and economies, yet their populations are declining worldwide from habitat loss and disease. Some bats are primary pollinators for fruits and other produce and help disperse seeds of plants that restore forests. Bats prefer roosting near open bodies of water, parks and fields where they can catch the most insects during their nighttime forays.

During the day, bats prefer to roost in tight crevices such as cracks in rocks, and in awnings of buildings where they are protected from predators. They may also roost in attics, soffits, louvers, chimneys and porches; under siding, eaves, roof tiles or shingles; and behind shutters. Still, bats need to be treated with respect and care if they enter a house. Usually they enter through an open door or window, but can fit through openings as small as one-half inch in diameter. Without doubt, the bat’s primary goal is to escape back outside.

If you encounter a bat, don’t panic. Bats are rarely aggressive, even if they’re being chased, but they bats in cagemay bite in self-defense if handled. It is true that bats can carry rabies and should never be touched with bare hands.

If bats begin to roost in your attic or somewhere you don’t want them, your best bet to solve this problem is with is integrated pest management. First, do not simply wait for bats to fly out at night. Not all bats leave the roost at the same time and some may stay inside for the night, especially the young. To properly seal holes, you can use caulking, flashing, screening or heavy-duty mesh. Ask a professional the best way to evict the roosting bats. Often the answer is a one-way door. In any event, get rid of your bats before mid-May or after mid-September to avoid trapping young.

Every state has unique laws related to bat protection, and it may be illegal for anyone, including animal control officers and exterminators, to kill certain bat species. No pesticides are licensed for use against bats and it is a violation of federal law to use a pesticide in a way not described on the label.

When you decide to get rid of bats you should provide a near-by shelter, such as a bat house. Install the bat house a few weeks before you eliminate their indoor roost, to allow the bats time to find the new shelter. Trees are generally not good places for bat houses since they are accessible to bat predators like raccoons and cats. However, if you do use a tree, add a metal protector guard. A pole mount in a garden or field is the preferred bat house location.

Community bat houses can be educational. Families, like ours, can sit outside at sunset and watch the bats on their nightly fly-out. It seems that there really were fewer mosquitoes this past summer, perhaps because of the presence of more bats.

More information on bats from the Smithsonian Institution (http://www.si.edu/Encyclopedia_SI/nmnh/batfacts.htm)

More information on Integrated Pest Management: http://www.epa.gov/managing-pests-schools/introduction-integrated-pest-management

More information on Safe methods of pest control: http://www.epa.gov/safepestcontrol

Marcia Anderson, who has a doctorate in environmental management, works with EPA’s headquarters on issues related to pest management in schools. She formerly worked in pesticides for EPA Region 2 and has a home in Lyman, Maine.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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The Story of One Cave, and the Bats who Live There

By Vanessa Madden

Myotis sodalis (Indiana Bat)

The year is 1722, French explorer Philipp Renault, guided by Osage Indian legends, emerges from the mist on the Meramec River. Just as the Osage had told him, a large opening could be seen in the bluff above. A cave of gold was waiting to be discovered………. But, as is often the case when French explorers read too much into Osage legends, the promise of gold was never realized. However, the caves along the Meramec River do contain one of nature’s greatest treasures, bats. I doubt the bats made much of an impression on Renault. But at the time, the numerous passageways of this 4.6 mile cavern system undoubtedly provided plentiful wintering and roosting habitat for native bats. Today we know that Missouri caves are home to 14 species of bats (learn about Missouri bats), three of which are federally endangered (Indiana Bat, Gray Bat, and The Ozark Big-Eared). Unfortunately, the cave was not to be left alone. Saltpeter was discovered. Saltpeter was an important resource at the time because it was a key ingredient in gunpowder. What followed was 144 years of mining saltpeter out of the cave, which ended when Confederate troops destroyed a Union gunpowder plant operating inside the cave itself. My guess is that blowing up large amounts of gunpowder was a bit annoying to the bats. Things quieted down a bit after the civil war. The cave was sometimes used by local residents for summer parties and dances. However, people are curious. Word spread of the beautiful features inside the cave. So, in the 1930’s, the cave was opened to the public. Today, tours are conducted year around.

Corynorhinus townsendii ingens (Ozark Big Ear) Wikipedia

Mankind’s use of the cave over the last 300 years has greatly affected the ability of bats to use the cave as habitat. Many of the original entrances and passageways were sealed off, in an attempt to keep trespassers out of the cave. Year around tours have driven the bats into quieter caves nearby. Perhaps the most unexpected threat to the cave ecosystem was the discovery that groundwater contamination at a nearby hazardous waste site was impacting the cave’s air and water quality.

Myotis Auriculus (Gray Bat)

Ironically, all of the historical causes of declining bat populations pale in comparison to the potential affect of a little fungus known as G. destructans or “white-nose syndrome.” Just as its name implies, this fungus has destroyed over 5 million bats in North America, and it is spreading. The human story of this cave is one of adventurers, outlaws, and entrepreneurs. Nature’s story, however, is one of encroachment and loss. Much has been written about the value of bats to mankind. For example, they consume vast quantities of insects (600/hour according to University of Missouri researchers) and pollinate plants. Perhaps more importantly, they have an intrinsic value that we all can recognize. Now, with native bats facing perhaps their greatest challenge yet, we must do all that we can to protect these diminutive creatures. Venessa Madden is a Midwestern girl who grew up playing in creeks and pastures.  Exploring nature motivated her to become an ecologist. She has been with EPA for 14 years, and currently works as an ecological risk assessor.  She is a past winner of EPA’s prestigious James W. Ackerman Award for Ecological Risk Assessment, and conducted a first ever Baseline Ecological Risk Assessment which included evaluating an inhalation pathway for bats.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Bats: More than Tiny City Vampires

By Marcia Anderson

Bats have a reputation for being spooky or even dangerous, but they are some of the most beneficial animals to people. They are the most misunderstood and needlessly feared of the world’s creatures. Furthermore bats do not entangle themselves in hair as widely believed and they will not encounter people by choice but only in self-defense.

Very few species of bats are vampire or blood consuming. Out of the more than 1,100 different species of bats worldwide, there are only three species of vampire bats and none live in the United States. Vampire bats only live in tropical climates and typically feed on cattle, poultry or other livestock. Most North American bats have small teeth for eating insects and do not gnaw through wood or other building materials like rodents.

All of the NJ and NY bats are insectivores and they need to eat and drink every night. Their food requirements are well served by open grasslands and parks, where insects are abundant. They feed on a huge variety of night flying insects, including mosquitoes. A single little brown bat can eat 3,000 mosquito-sized insects per night.

Bats are essential to maintaining healthy ecosystems and economies, yet their populations are declining worldwide due to loss of roost trees, disturbance of dens, and outright persecution by man. Enjoy your bananas, mangos and guavas – and thank the bats that help to bring these fruits to your table. Some bats are primary pollinators for fruits and other produce and help to disperse seeds of plants vital for natural restoration of forests.

During the day they prefer to roost in tight crevices such as cracks in rocks, under exfoliating tree bark and in awnings of buildings. These locations provide protection from predators and stable temperatures. They also prefer roosting near open bodies of water. Bats can enter city buildings, especially near parks, through openings as small as one-half inch in diameter. Bats may roost in attics, soffits, louvers, chimneys and porches; under siding, eaves, roof tiles or shingles; and behind shutters. In stadiums and parking garages, bats sometimes roost in expansion joints between concrete beams.

Don’t panic. Bats are rarely aggressive, even if they’re being chased, but they may bite in self-defense if handled. As with any wild animal, bats should never be touched with bare hands. More

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.