Do you want to know how amazing bats are? I hear you saying, “Why am I learning about bats on Homestead.org?” What could they possibly have to do with homesteading? If you can hang with me, I will explain the advantages of putting up a few bat houses on your property.
The facts are amazing and should have all of us running out to buy or build hundreds of bat house. One little brown mysotis, (little brown bat) can catch 1,000 or more mosquito-sized insects in an hour. A colony of 150 big brown bats can catch enough cucumber beetles each summer to prevent the egg laying of 33 million rootworms. Bats catch and eat cucumber and June beetles, stinkbugs, leafhoppers, cutworm and corn earworm moths. Many garden and crop pests flee areas where they hear bat echolocation sounds. According to Bat Conservation International, the 20 million Mexican free-tailed bats that spend summers in Bracken Cave, Texas, eat up to 200 tons of insects in a single night over the surrounding towns and croplands.
If that isn’t enough for the bats to take on, they are also very important pollinators and vital for seed dispersal in the tropics. There are over 1,000 kinds of bats in all environments except in the most extreme desert and polar regions.
Now, all these facts have your attention, I bet. Before you leap into bat-house buying or building, wait, there is more to learn and understand before putting up those bat houses.
Most homesteaders work hard to do the “green thing” in their gardens and fields, trying to use natural and organic methods for insect control. Encouraging bats to spend the spring, summer, and fall around your homestead is an easy and natural approach to insect control.
Now, what is the next step? You are enthused, correct? It is probably best not to waste time or money on the small bat houses available at feed or pet stores. Those might attract a few bachelor bats but not nursery colonies. The most successful bat houses have roost chambers at least 20 inches tall and at least 14 inches wide. Taller and wider houses are even better. Rocket boxes, a newer pole mounted design with continuous 360 degree chambers should be at least 3 feet tall. All houses should have three to six inch landing areas extending below the entrances. Single chambered houses should be mounted on wooden or masonry buildings, which will help to buffer temperature changes. Houses with at least three chambers are more likely to provide appropriate ranges of temperature and better accommodate the larger numbers of bats typical of nursery colonies.
Next is a brief list of what should and should not be used in a bat house and where it should be placed. Detailed plans for building bat houses and how and where to install them can be found at Bat Conservation International; the University of Nebraska-Lincoln Extension: Institute and Natural Resources; the U.S. Fish and Wildlife Service; and “The Bat House Forum,” which can be found online and is free to join. This forum has information from people building bat houses and experimenting with different building materials.
When building your bat house, do not use pressure treated wood, which contains chemicals that may be toxic to bats. Bat houses need to be painted or stained in the color prescribed for your area. Do not use oil based products. The colder your area is in the spring and summer months, the darker the paint color. Bats like dry, warm, draft free houses, so careful calking and painting are important. Do not use metal mesh on landing and inside surfaces, it will tear at the bats wings and feet. Use only UV resistant plastic mesh or put 1/4- to 1/2-inch grooves on the wood surfaces for footholds. Recommended mesh size is 1/8-inch or 1/4-inch mesh.
Where the bat house is located is another critical cause of bats not using a house. Sun exposure and heat absorption must be carefully considered. Ventilated houses with tall chambers allow bats to move vertically to find the best daily and seasonal temperatures. Bats in nursery colonies like a warm house. Houses should face southeast for the most sunshine and warmth. Bat houses should be within a quarter of a mile of permanent fresh water. Bat houses should be placed on poles, metal or wood, at least 20 to 30 feet from the nearest tree branches or utility wires. Predators can use trees and wires to more easily hunt bats. The bottom of the bat house should be 12 to 20 feet above the ground. If a wood pole is used, a predator guard is needed to keep snakes and raccoons from climbing the pole to eat the bats.
If all this bat house information is too daunting for you, there are other things a landowner can do to attract bats. Bats are losing their natural habitats around the world because of increasing land development, agriculture and deforestation. In many cases, bats can adapt to changes if their needs of water, insect prey, and roosts are taken care of. Putting up bat houses is a great roosting alternative but planting and preserving native vegetation that attracts and supports a variety of non-pest insects for bats to feed on; decreasing disturbance and destruction of caves and mines; and protecting abandoned buildings are other ways to help bats. Leaving snags and tree hollows in forest and woodland to serve as natural homes and supplying open water resources where bats can drink on the wing are all excellent choices for helping bats survive the changes in their habitats.
To better understand bats—their behavior and what they need to survive—it is important to know more about their lives. Most bats that live in temperate regions, such as the U.S. and Canada, mate in the fall just before hibernation. Ovulation and fertilization from the fall matings takes place in the spring as the females emerge from hibernation (the female stores the sperm in her reproductive tract over the winter). Pregnant females then move from hibernating sites called hibernacula, to warmer roosts—which could be your bat houses!—where they form nursery colonies. Birth occurs about a month and a half to two months later. The young grow rapidly, learning to fly within three weeks. While the pups are being reared, males and non-reproductive females segregate into separated groups called bachelor colonies. Bats are, for their size, the slowest reproducing mammals on earth. On average, mother bats rear one young per year and do not give birth until they are two or more years old. They are long lived and some species can live 15 to 20 years. Bats can weigh as little as two grams or as much as two pounds. Bats are the only mammals that can fly! Amazing!
Contrary to popular belief, they do not fly into your hair and they are not blind. Bats have excellent eyesight, but communicate and navigate with high frequency sounds. In cold winters, bats are forced to migrate or hibernate. Most travel less than 300 miles to find a suitable cave or mine, where they remain for six months or more surviving on stored fat reserves. Bats are loyal to their birthplaces and hibernation sites and pass down information on how to find these sites from generation to generation.
Most eastern bats spend the winter hibernating in caves and move to trees or buildings for the summer. Some do spend all year in caves and others, like the tree bats, never see a cave. They roost in trees in the summer and tree hollows for the winters. As hollow trees are cut down, the bat boxes are needed for bats to survive. This is very important from April to August when females are looking for safe and quiet places to raise their pups. Both mothers and newborns are very sensitive to being disturbed. One reason to put up bat houses is to balance the loss of habitat that bats of all species are experiencing, but another reminder of the importance of bats from the U.S. Fish and Wildlife Service is that a typical summer colony of 100 bats, feeding 200 days will consume more than 2,200 pounds of insects or approximately 600,000,000 bugs!
Having more places for bats to roost might, in some small way, help stop or slow the spread of White-nose Syndrome which has, according to the Center for Biological Diversity news update on March 14, 2013, has killed over 6.7 million cave-dwelling bats in eastern North America. It is hard to even imagine that we have lost over 6.7 million bats because of a fungus! As of March 2013, it has been found in many bat populations in 22 states and 5 Canadian provinces. White-nose Syndrome is transmitted from bat to bat by spores of Geomyces destructans, a cold loving fungus. It is carried between caves by humans—on clothing, footwear and caving gear. White-nose Syndrome does not affect people, pets, or livestock, but is lethal to hibernating bats, killing 90% or more.
WNS was first detected in New York State in February 2006 and is spreading south and west. It is believed by Bat Conservation International and the National Park Service that the fungus was brought over from Europe by people who had not decontaminated their caving gear after using it in European caves where the fungus is known to be found. This fungus kills because it causes bats to awaken more often during hibernation and to use up the stored fat reserves that are needed to get them through the winter. Infected bats emerge too soon from hibernation and are seen flying around in midwinter. These bats freeze or starve to death.
So, how can we help? The U.S. Fish and Wildlife Service has the following suggestions:
Avoid possible spread of WNS by humans, by staying out of caves and mines where bats are known to hibernate.
Honor cave closures and gated caves.
Learn why “decontamination” is critical if you do go caving in approved caves.
Stay out of all hibernacula when bats are hibernating in the winter. Every time they are disturbed they use up the fat that is needed for energy to survive the winter months.
Be observant and report unusual bat behavior to your state natural resource agency or your state wildlife agency, such as bats flying during the day in winter or unexplained bat deaths.
Encourage your state and federal legislators to fund WNS research.
Most importantly, take care of bats! Minimize disturbance to natural bat habitats around your homestead; reduce outdoor lighting; do little to no tree-clearing; protect streams and wetlands. Then construct or protect homes for bats on your property.
Equally important is to educate yourself about bats by visiting websites and attending educational programs or events. Educate your friends and families about the benefits of bats and the WNS crisis.
Now, I know this is a great deal of information to take in, but don’t feel overwhelmed and give up; just remember the thousand mosquito-sized insects just one bat can eat in just one hour. Bat biologist John Whitaker, documented that a single colony of 150 big brown bats, which can live in one bat house, can eliminate 38,000 cucumber beetles, 16,000 June beetles, 19,000 stinkbugs and 50,000 leafhoppers each summer. This estimate does not consider the many other insects these bats eat. Whitaker concluded that by eating 38,000 cucumber beetles the bats protected local farmers from approximately 33 million root-worm larvae that the beetles would have produced.
The Bat Builder’s Handbook lists questions people often ask about putting up bat houses. Will having bat houses in my yard interfere with attracting birds? No, they rarely compete for food or space. Will bat droppings pose a health threat to my family? No more so than bird or cat droppings would. What are the odds that a sick bat will endanger my family with rabies? Like all mammals, bats can contract rabies but less than one-half percent do and the infected bats die quickly and rarely become aggressive. The odds are remote if you simply do not attempt to handle bats.
I hope all this information will help and motivate you to add bat houses to your homestead. I also hope the information will inspire you to learn more about the bats in your area and to educate your family and friends on the extreme importance bats have in our lives. I have placed five bat houses on various prairies and ranches in my area and never miss a chance to talk to people with my opening line, “Do you want to know how amazing bats are?”
National Park Services, U.S. Department of Interior.
University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources.
U.S. Fish and Wildlife Service, publications on bats.
“The Bat House Forum” an online resource for bat house plans and how to attract bats to the houses.
Appalachian Bat Count, Bureau of Wildlife Management, Harrisburg, PA
Indiana State University Center for North American Bat Research and Conservation