(The following is a news release published by the United States Department of Agriculture, Forest Service, on October 24, 2018.)
Bat Week is an annual, international celebration of the role of bats in nature. Bat Week is organized by a team of representatives from across the United States and Canada from conservation organizations and government departments. This year, it falls on October 24-31.
Worldwide, there are more than 1,300 species of bats, which is almost 20 percent of all mammal species. Bats live everywhere on Earth except the most extreme desert and Polar Regions. So, no matter where you live, chances are there are bats living near you.
Bats are the only mammals that can truly fly. The structure of the bat’s wing is actually a modified hand. The finger bones are elongated to support a thin membrane of skin that extends between each finger, arms, and body. The membrane of a bat’s wing is living tissue similar to the tiny flaps of skin joining the bases of our human fingers. These “hands” have been adapted for flight, and the flexible skin and many moveable joints make bats exceptionally agile fliers.
Contrary to popular belief, bats actually have good eyesight (similar to that of humans). Some bats use their eyes to find food, but for bats that eat insects, eyesight isn’t their main means of navigating or locating prey. Bats use echolocation, they emit a very high-pitched sound (higher than human hearing range) that bounce off obstacles in their path, like trees, other bats, buildings, and their main target insects. Bats use those reflected sounds to identify what an object is, how big it is, and what direction it is moving.
With all the flying and echolocating, bats burn a large amount of calories. So come nightfall, bats are busy searching for- and eating- all kinds of foods. A single bat can eat up to its body weight in insects each night. Eating all these insects helps protect our food crops and forests from insect pests, saving farmers and forest managers billions of dollars each year. The majority of bats in North America eat insects, including moths, beetles, aquatic insects, and flies.
In 1974, biologists discovered that some male bats sing, very much like songbirds do, and they warble for the same reasons: to defend territories and to attract mates. Researchers revealed that the tunes of some bats are even more complex and similar to bird song than first suspected. These bats’ melodies are structured, have multiple syllables, phrases, repeated patterns, and, of course, rhythm.
Bats are wonderfully beneficial creatures. Without bats, Earth would be a very different and much poorer place. They play an ecological role that is vital to the health of natural ecosystems and human economies around the world. Yet they are also among the most misunderstood of animals – routinely feared and loathed as sinister denizens of the night. However, in China, bats have long been celebrated as symbols of good luck and happiness.
Although we may not always see them, bats are hard at work all around the world each night- eating tons of insects, pollinating flowers, and spreading seeds that grow new plants and trees. Step outside around dusk and take a few moments to look for bats in your neighborhood.
Many of the bat species consume vast amounts of insects, including some of the most damaging agricultural pests. Others pollinate many valuable plants, ensuring the production of fruits that support local economies, as well as diverse animal populations. Fruit-eating bats in the tropics disperse seeds that are critical to restoring cleared or damaged rainforests. Even bat droppings (guano) are valuable as a rich natural fertilizer. Guano is a major natural resource worldwide, when mined responsibly it can provide significant economic benefits for landowners and local communities.
Bats are so effective at dispersing seeds into ravaged forestlands that they’ve been called the “farmers of the tropics” and these dropped seeds can account for up to 95 percent of the first new growth.
The ability of bats to fly long distances is also another benefit to plants. Some bats use echolocation to find flowers. Bats service many plants that we use for medicinal, cultural and economic purposes.
Bats are often considered “keystone species” that are essential to tropical and desert ecosystems. Without bats’ pollination and seed-dispersing services, local ecosystems could gradually collapse as plants fail to provide food and cover for the local wildlife. Consider the great baobab tree of the East African savannah. It is critical to the survival of many wild species that it is often called the “African Tree of Life.” Yet it depends almost exclusively on bats for pollination. Without bats, the “Tree of Life” would die out, threatening one of our planet’s richest ecosystems.
The International Union for the Conservation of Nature (IUCN) currently lists 24 bat species as Critically Endangered, meaning they face an imminent risk of extinction. Fifty-three others are Endangered, and 104 bat species are considered Vulnerable. Bats also are among the most under-studied mammals. The IUCN lists 226 bat species as “Data Deficient”– there is simply too little information available to determine their conservation status.
The IUCN assessed nearly a third of bats are considered either threatened (vulnerable, endangered, or critically endangered) or data deficient, indicating the need for more conservation attention to these species.
Loss of habitat remains the most widespread peril worldwide. The forests many bats use for roosting and/or foraging for food are disappearing at a frightful rate – shrunken by timber harvests or cleared to make room for farm crops, mining operations, cattle pastures or cities. This is especially critical in the tropical rain forests, with both a rich diversity of bats species and a precipitous loss of woodlands.
Countless bats are being driven out of roosts in caves and abandoned mines because of inappropriate guano mining (bat droppings, or guano, are a valuable fertilizer) or thoughtless tourism. During the winter months, large numbers of bats hibernate in caves and mines. If roused from hibernation, often by human disturbance, bats can burn through the stores of fat they need to survive the winter.
In much of the world, bats are still casually killed because of harmful myths and misplaced fears. In Latin America, whole colonies of beneficial bats are routinely destroyed in the mistaken belief that all bats are vampires. (In reality, only three of the more than 1,300 bat species feed on blood and all are in Latin America.)
White-nose syndrome (WNS) is a disease that affects hibernating bats and is caused by a fungus, Pseudogymnoascus destructans, or Pd for short. Sometimes Pd looks like a white fuzz on a bat’s face, which is how the disease got its name. Pd grows in cold, dark and damp places. It attacks the bare skin of bats while they’re hibernating in a relatively inactive state. As it grows, Pd causes changes in bats that make them become active more than usual and burn up fat they need to survive the winter. Bats with white-nose syndrome may do strange things like fly outside in the daytime in the winter.
Biologists first saw bats sick and dying from white-nose syndrome in 2007 in caves near Albany, New York. However, cave explorers in that area had taken a photo of bats with a white powder on their noses the year before, so white-nose syndrome has been in North America at least since 2006.
How Pd got here or where it’s from is unknown. Pd spores can last a long time on surfaces such as clothes, shoes and outdoor gear, so even though people do not get white-nose syndrome, they can unknowingly move the fungus from one place to another – the most likely way that Pd found its way to North America.
No matter how it got here, white-nose syndrome continues to spread rapidly across the United States and Canada, mostly through bat-to-bat contact. Pd can also live in areas without bats, so bats can pick up the fungus from the environment, too. Go to the latest white-nose syndrome map to see where cases have been confirmed.
White-nose syndrome has killed millions of bats in North America. At some sites, 90 to 100 percent of bats have died. Several species are affected, with the hardest-hit being the northern long-eared bat, little brown bat, and tri-colored bat. Other species, like the Virginia big-eared bat, have been found with Pd, but they don’t show signs of being sick with white-nose syndrome.
Pd was unknown to science until it was found on North American bats. After that, researchers began looking for it elsewhere and found it on bats in Europe and Asia, where bats do not appear to get as sick from the fungus as they do in North America.
There is no cure for white-nose syndrome, but scientists from all over the world are working together to study the disease, how it spreads and infects bats and what we can do to control it. Several experimental treatments, including a vaccine and making changes to bat habitats, are in progress and will hopefully lead to increased survival of bats from this devastating disease.
The Forest Service is a leader in fungal pathology, invasive species control, monitoring design, and bat ecology. We are collaborating with diverse partners to control the spread of the WNS fungus and reduce disease-induced mortality.
USFS maintains healthy populations of bats by:
- Closing caves where spread of the WNS fungus by humans poses a concern.
- Conducting, participating, and volunteering in Bat Blitzes.
o A Bat Blitz is a coordinated, intensive survey designed to sample the bat community in an extensive area.
o Volunteers put up nets and capture bats to find out what species of bats live and frequent the area. Forest Service scientists and researchers often participate as volunteers.
o Experts invite the public to educate them about bats and their importance.
o Every state conducts Bat Blitzes in national forests and grasslands and other areas.
- Establishing disinfection protocols to minimize the spread of the fungus by humans.
- Initiating experimental treatments of bats to reduce the impact of WNS once bats are affected.
- Setting up acoustic detectors in each national forest to conduct acoustic surveys through NABat.
o NABat is a collaborative partnership to systematically document bat populations.
o Their primary methods of monitoring bats include: Mobile acoustic surveys along driving transects, acoustic surveys at stationary points, external roost counts, internal winter hibernaculum counts, and internal maternity colony counts.
- Installing iron grates over abandoned mine entrances.
o 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.
The U.S. Forest Service has coordinated with the Minnetonka Cave concessionaire to provide tourists information on WNS, bat ecology, and cave geology. Minnetonka Cave is rebuilding the entrance, working on creating a new cleaning station for shoes and clothing to protect the cave’s wildlife. Nearly 1000 little brown bats and other Myotis species make Minnetonka their home.
The U.S. Forest Service also is putting up a new gate at Logan Cave to minimize disturbances. Once a year, the Forest Service goes in with the Utah Department of Wildlife Resources to count bats and test for the WNS fungus.
Across the nation, the Forest Service is collaborating with multiple partners to ensure the bat population and awareness rises and WNS is cured.
How You Can Be a Bat Hero
- Plant a garden with a water feature and compost pile!
- Join or organize a stream clean up or invasive plant pull.
o Parks, forests, refuges, and monuments need your help to battle invasive plants and to keep habitats clean and green.
o Check with your favorite local green space for opportunities to participate and contact your local park authority to find out how to organize your own!
- Monitor bat boxes for occupancy.
o Lots of bat boxes are installed in parks, but they often go unwatched. See if your local park has bat boxes and if you can monitor the boxes and record when the bats arrive and how many there are.
- Attend a bat program at a park or nature center. Share what you learn with others.
- Even small adventures in nature help everyone appreciate the natural plants and animals that surround us. Don’t forget to get the family outside at sunset and after dark to watch bats!
Build a Bat Box
- Order a bat house kit from a reputable vendor or make your own bat house instead!
- Make a bat house that mimics the space between bark and a tree trunk. This would be the bats’ ideal nursery.
- The box should be placed at least ten feet above the ground in an open area orientated south-southeast (135° azimuth is optimal) where it receives at least seven hours of direct sun.
- The box will be more attractive to bats if it is within 1,500 feet of a permanent stream or pond.
o Bats need a drink on very hot summer days, and the fresh water guarantees a nearby feeding zone.
- Habitat diversity will also attract bats.
o A combination of forests, clearings, and wetlands will produce different types of insect activity at different times throughout the summer, assuring a constant supply of food.
- The box should be within 10-30 yards of a tree line to provide quick cover from predators, such as owls.
- Painting or staining the outside of your bat house increases the chances of attracting bats.
o Dark brown or black paint or stain on the exterior of bat houses in the North increases the temperature in the house.
- Carefully caulk all exterior joints before painting.
- Mounting your new bat house directly on a structure where bats are being evicted will almost guarantee a successful bat house occupation.
- Be careful not to mount the bat house directly over windows, doors, and walkways.
o Bat excrement may stain certain paints on the structure. Minimize this by using spacers between the bat house and the structure.
- Inspect the bat house interior using a spotlight.
o If bats are present, wait until later in the season to do routine maintenance. Once during each winter the bat house should be inspected carefully for broken seams.
- Remove wasp/hornet nests in the winter using a long, thin rod or stick only when bats are not present.
- Check carefully before cleaning because shadows can hide solitary bats in what first seems to be an empty box.
- Write letters to the editor or comment on media segments that portray bats in a negative light.
- Help friends and family understand that bats are beneficial and need our help.
- Ask your town, city, or state officials to make a formal proclamation.
A Special Note on Caves
For cave dwellers, please stay out of caves and mines where bats are hibernating and honor cave closings. Follow the National WNS Decontamination Protocol to clean and disinfect clothes, footwear, and equipment used in caves or mines. Report bats showing signs of white-nose syndrome, and bats that are dead, dying, or appear diseased, to a forest ranger. For more information on WNS, click here.
Rinse equipment, as appropriate, thoroughly in clean water, particularly items that may contact humans, bats, or sensitive environments. Allow all equipment to completely dry prior to the next use. Decontaminate the equipment bins, sinks, countertops and other laboratory, office, or home areas with the most appropriate applications or products in Table 1.
(Cover photo: An adult Rafinesque’s big-eared bat, courtesy USDA-Forest Service.)