Wildlife Education - Information and Advice for the Safe Removal of Bats from Attics

Bats in the Attic

This is an educational guide to assist you if you have a bat problem in your home or building and want to get rid of bats in the attic. It is written by a professional bat removal expert who has performed over 500 bat removal jobs, in every type of building, with a 100% success rate, and without ever killing a bat.

First off, I have to say that if you know what you are doing, you can solve your bat problem permanently. But it is not an easy task, especially if you are not experienced. I trained with an expert for two years, got my Bat Conservation International certification, and even then I required many jobs on my own before I truly got good at bat removal from attics and buildings.

Second, I want to make it clear that the and only legal, the only humane, and by far the most effective, way to remove bats from an attic is with a live exclusion. None of the bats are killed in the process.

HELP: If you need professional help in solving your bat problem, please click on my Hiring Advice and 2014 Directory of Bat Removal Professionals serving every city in the USA.



Above are some photos I've taken at various bat jobs. On the left, you can see a group of bats swirling inside a house. In the middle, is a huge swarm of bats, over 1000, entering and exiting a hotel 8 stories up. On the right is a photo inside an attic with a large bat infestation.

Step-By-Step Instructions For Removing Bats From Attics

STEP 1 - Inspection: You have to find out how the bats are getting in and out of the building, where they are living, what species they are, and what damage they have caused. They fly out at dusk, and fly back at dawn. Not all at once, and they make several trips in and out per night. They usually roost in tight, hot areas in the structure. This means that they often roost in attics. However, they are not out in the open. They usually crawl down walls and wedge into gaps behind wood beams, fascia boards, etc. They can leave millions of droppings (guano) all over your attic. The exact species of bat is very important in performing the exclusion
properly, because of different sizes, behaviors, and most of all birthing seasons. To learn more in detail, click how to perform a bat inspection. If it is not the birthing season, you can do a bat removal project. You absolutely do not want to remove the bats during the maternity season, when there are young, flightless bats in the attic. That will result in disaster. Read more about bat maternity season.

STEP 2 - Pre-Sealing: The bats usually have several entry holes and gaps leading into the house. The key to a proper bat removal project is to find all of these areas. The holes and gaps are usually tiny, about a half-inch (yes, a half-inch), and very easy to miss. In order to remove the bats, you have to funnel them out. But if they can enter via dozens of spots, you want to seal off potential entry holes beforehand. Never seal a primary entry/exit spot before an exclusion. An expert can easily tell the difference. Read more about how to seal your house against bats here.

STEP 3 - Exclusion: Install one-way exclusion devices on the primary entry/exit areas. Depending on the architecture, this may be exclusion netting, screening, funnels, or cones. Every building is different, and the bats relate to the architecture in very specific ways that require selecting the proper device(s). The exclusion netting or funnels must be set perfectly to allow bats to fly out naturally at night, but then not be able to fly back in. That is the main principle. Simple in concept, but very hard to get right! And it is crucial that it is done perfectly, or you'll have a big problem on your hands. Read about the bat exclusion process.

STEP 4 - Seal-Up: After you are 100% certain that all the bats are out, remove the exclusion devices and seal the entry holes shut. Bats live a long time and remember for a long time, and will attempt to re-enter the building for a long time. Perhaps for the next few seasons. But they are fragile animals, and they can't claw or chew their way back in, so if you do your job right, you'll never have bats inside again. A variety of materials work well, from plastic or metal screening, to caulk, to high density polyurethane, depending on the situation.

STEP 5 - Cleanup: The bats have left droppings in your attic or walls, perhaps by the million. Also, urine. In very small amounts it's not a huge deal. But in the average case, there is enough to corrode wood and drywall, and to grow mold. Though it's unlikely, this mold can cause health problems for people, so I must mention it. In most cases, the bats have left behind a strong odor as well. The attic and walls and other areas the bats have contaminated should be cleaned. Read more about the bat cleanup process here.

Okay, those are the basics! But it's very important for you to understand that a bat removal job is by no means simple. There is only one way to do it right: with a live exclusion. Repellent products and devices have a 0% success rate. Any attempt to trap or kill the bats will only result in a failed job and frustration, (not to mention it's illegal to attempt), so never attempt anything but a proper live exclusion during the non-maternity season. Because of my experience, and knowing what it takes to do it right, and the consequences of failure, I highly recommend hiring a professional who has a lot of experience. I can help you hire the right company, and how to ask the right questions on the phone and in person before you commit to hire someone. Read my Hiring Advice - What to Ask guide here.

SECRET PRO TIP FOR GETTING RID OF BATS IN THE ATTIC: I often do the bat exclusion and seal-up work at night! Yes, I'm high on a ladder and crawling all over a roof at night. Why? Because it's so much easier to spot all the gaps and crack at night while focusing a high-beam headlamp on the building. You might think this is silly or counter-intuitive, but again, I've done hundreds of bat jobs, and I've learned that the work is more effective this way. You'd be amazed at the holes you see at night that escape you by day, and the bat behaviors you see that ensure 100% success. Remember, it's not like I prefer to be working in the middle of the night! It's just that it helps get the job done perfectly, and perfection is required.



Frequently Asked Questions

Q: Can I just use some sort of repellent product to get bats out of the attic? Like a powder or spray? What about a natural home remedy? Will a bright light or noises work? How about those high-pitch sound machines?
A: Unfortunately, no repellent of any kind has been shown to work in the slightest. It would actually be very nice, because then we could remove bats easily (and harmlessly, just like a real exclusion). Alas, for a variety of important reasons, no repellents work. You can read more about bat repellent here.

Q: Can I kill the bats with some sort of poison or fumigant?
A: Absolutely not! Aside from being illegal and immoral (even if you don't give a crap), every attempt I've seen has resulted in disaster for the property owner. Why even attempt poisons, when a live exclusion is so much more effective? You can read more about how to kill bats with bat poison here.

Q: Can I trap the bats in some sort of bat trap?
A: This would be pointless, not to mention very harmful to the bats, and usually resulting in a failed exclusion. You can't relocate bats, because they will migrate hundreds of miles back to their roost. And it's illegal to kill them. But most of all, the traps that do exist are cumbersome and the bats don't enter them very well, so they result in failed jobs. Read more about bat trapping here.

Q: Is there any way to prevent bats from entering my house?
A: Of course! Seal every gap, crack, and hole in your house. Pay particular attention to the roof lines - fascia boards, gable vents, dormer peaks, soffit eave gaps, etc. Any gap of 1/2 to 1 inch is especially desirable. Bats can't chew, so caulk or polyurethane sealant works great! Of course, if you already have bats in your attic, then you can't seal the holes shut yet. Read about bat prevention here.

Q: Can't I just seal the entry holes shut at night when the bats are out?
A: Good question, but no. Not all of the bats leave at the same time. They go out in groups and shifts, and return back and forth all night. At no time is 100% of the colony out at once. So if you seal at night, you will be sealing some in. You need to set the bat exclusion devices.

Q: Why do bats like to live in attics?
A: Buildings, attics in particular, provide a warm, dry, safe space to live in and raise baby bat pups. An attic is sort of like a cave - but even better, because it's protected from predators, and high off the ground, making entry and exit easy.

Q: What species of bats typically live in attics?
A: There are about 45 species of bats in the US, but only colonizing bats live in attics. In the US, this really only means a few significant species, most commonly the Big Brown Bat and in larger numbers, the Little Brown Bat in the northern states, and in the southern states, you'll find Evening Bats, but most commonly the Brazilian, aka Mexican Freetail Bat.

Q: What problems do bats cause when they live in a building?
A: Most people notice the odor first. If the colony is large enough, people also notice the noise they make. They are generally harmless animals, they don't chew on wires like rodents do, but the main problem they cause is that they poop and pee a lot. Each bat can poop 20 pellets per day, and if you multiply that number times hundreds of bats over a couple of years, you get an attic full of bat guano! It smells bad, it corrodes wood and drywall, and it can grow mold. Read more about bat guano, aka bat poop here.

Q: What if I have bats in my chimney?
A: Chimneys are a different architecture than an attic, of course. The methods for removal are different. First of all, DO NOT START A FIRE. Burning bats will flood your living room. Special netting must be set on top of the flu. Read more about bats in the chimney here.

Q: What if I have bats living under Spanish Barrel Tiles on my roof?
A: This happens a lot, particularly in southern states, where these roofs are more common. It's a very challenging scenario, but one that I have solved dozens of times. In short, it requires a lot of meticulous sealing and wide area netting. Read more about bats in a barrel tile roof here.

Q: What if a bat has gotten into the living quarters of my house, like bedroom or living room?
A: First of all, it's probably there because it was part of a colony living in your attic or walls, and it accidentally crawled into the living area. It's very rare that one just flies in. There are many methods used to remove the bat, such as picking it up with thick leather gloves, gently smothering it in a towel, the old tupperware and paper trick, etc. You can then bring it outside and watch it flutter away. Read more about how to catch bats inside the house here.

Q: How do I clean up the bat guano in my attic?
A: First of all, wear protective gear. I wear a biohazard suit and rubber gloves, but most importantly, a HEPA air filter mask. The bulk of the droppings can be shoveled out into plastic garbage bags, then looser droppings can be vacuumed up with an industrial vacuum with filter. Then it's important to fog the attic with a special enzyme-based cleaner that will eat away at remaining organic matter and kill pathogens. Read more about the bat guano cleanup process here.

Q: What is the bat maternity season? Why can't I remove the bats in the summer?
A: Interesting fact: the bats in your attic are actually all females! They are called a maternity colony, and they are in your attic in order to have a safe place to give birth to and raise their young. The males just roost outside, in tree bark, etc. Female bats give birth to only one baby bat per year, and raise it well. The young are born in late April - early June depending on species, and the young are growing and flightless until some time in August. You can't do an exclusion while the young are flightless, because they'll all either die or crawl down the walls of your house and many will find a way inside your rooms. Read more about bat maternity season here.

Q: Can I lure the bats out of my attic with a bat house? How do I build a bat house?
A: A bat house will NOT lure the bats out. Your attic is much better. It's hard to get bats to live in a bat house. They have to discover and adopt it on their own, and some bat houses lay dormant for many years. However, I think it's very nice to build bat houses, and I have instructions on how to build one, if you read more about bat house here.

Q: Do bats carry rabies and transmit them to humans?
A: Yes, but it is rare. Even though all warm-blooded mammals can carry rabies, for some reason there are different strains, and humans aren't susceptible to many of them. For example, many raccoons are rabid, but they don't pass the rabies on to humans. But for some reason, some of the strains in bats are transferrable to people, and thus most cases of rabies in the United States are due to bats. But the numbers are very low. Read more about bats and rabies here.

The Bottom Line

Bat removal is not easy, especially if you want to get rid of bats in the attic. As I said, I trained for many years and did dozens of jobs before I got good at it. Most of the do-it-yourself bat removal attempts that I see have ended in disaster, before I was called out. I do highly recommend that you hire a professional with experience to solve your bat problem. Click on my 2014 Directory of Bat Removal Professionals if you want to hire someone good in your city or town. I've researched this for many years. I have more in-depth info below, but you may just want to click any of the above links to answer your specific questions. If you have any special questions, feel free to email me.

Bat Facts And Removal
There are quite a few different species of bats in North America; however the ones that are known for colonizing are the species that most often cause problems. It is a general misconception that bats are related to mice or considered flying rodents. They are not. Among many biological differences is the fact their teeth don’t continuously grow unless worn down. Instead bats are more closely related to primates and shrews. People tend to be terrified of them but it’s important to note they are not aggressive and will not choose to attack a person. Even more critical is the important role bats play in the environment and ecosystems.

How Can You Tell Bats Are In Your Attic
It is not unusual for a person to find they have bats in their attic, garage or other outbuildings. Unlike larger nuisance animals like raccoons, it can be difficult to know you have a colony of bats until you have many. If you go into the attic often you may see signs of their residency more quickly. This can be in the form of piles of guano (bat waste) building up on the floor. One of the easiest ways to tell if you have bats is hearing their scraping, rustling or squeaking. These noises can come from your walls, attic or chimney. You may also see issues when outside around dusk or dawn. You can hear the slight peeping and see bats swooping around. Often people think this swooping is the bat diving in trying to attack people. In actuality, the bats are diving to snatch up bugs. If you hear this peeping and see bats it’s good to pay attention to where they go. Often you will see them head toward a section of the house and even disappear. This will help you know how they are getting in and you can use this knowledge when it comes time to exclude them. Another way to tell if you have a bat problem in a building is to look for signs of guano on the outside of a home. Often when they enter or exit a home they will leave droppings or urine. You may see staining around areas a bat can use to enter your home. Brown or grey streaks can be left near soffits, the roof and chimneys and are prime indicators of a bat colony. These stains are left by the oil on their skin and/or urine.

Why Are The Bats There
Though we don’t often see bats, different species inhabit every continent in America except for Antarctica because they are an animal that needs warmth. They are more abundant in rain forests and tropical climates. Maternal colonies choose caves to deliver their young because they want shelter and safety from predators. For this reason an attic, garage or barn can be an ideal space for them. If given the opportunity they will quickly sneak into your home and set up shop there.

How Do Bats Get In
Bats actually don’t need much space to enter your home. Some of the most common species only need an inch by half inch to get in. These spaces can be found in siding, under roof shingles, near paneling, near attic fans and by soffits. Generally bats are going to enter a home near the roof or attic. For this reason you will likely need a ladder if you are going to hunt for their point of entry.

What Kind Of Bats Are There
The most common bat in the U.S. is the Mexican Free-tailed bat and their numbers reach between 120 and 150 million. They are small, only 3.5 to 4.5 inches long and they can be different shades of brown or grey. The females live about 13 years and the males about 18. They form some of the largest colonies with numbers as high as 20,000. They gather to mate before hibernating and the females store the sperm inside of their body until after hibernation. At this time one egg is fertilized and then the female joins a maternity group. In this group females give birth to one pup and take care of it until it can fly and fend for itself which takes several months. They reach maturity at about eight months when they can start mating and raising their own young. The other commonly found bat is the Little Brown Bat. Very similar to the Mexican free-tail, the Little Brown Bat is also nocturnal, hibernates and feeds on large amounts of insects. When they hibernate they seek a cave that doesn’t dip below forty degrees Fahrenheit and in southern, warm climates they may not hibernate at all. These bats reach maturity between 6 and 9 months and babies are born between mid-June and July.

How To Remove Bats From The Attic
One of the first steps to getting rid of bats in the attic is to confirm they are there. Once you have spent the time confirming bats are in your home you’ll want to look for ways they are getting in. Many people think that they should trap the bats and get rid of them this way however this is not the best way to get rid of bats. Releasing them usually sends them right back to your home and trapping is difficult and dangerous for the person and the bat. Another popular mistake is sealing up the entrance where the bats are getting in. This leaves no way for them to easily get out and will end up causing these important little creatures to die in your attic. The only good way to get rid of bats in your attic is to perform exclusion. It is absolutely critical this isn’t done during between May and the end of August. During these months the bats in your attic are either delivering their baby or taking care of the flightless pup. If you exclude the mothers now you can end up with a bunch of babies dying in your attic. Not only is this cruel it is illegal almost everywhere as bats are protected. Getting rid of bats in your attic can be tricky and time consuming but it can be done. Once you have found the ways the bats are getting in and have insured you aren’t getting ready to exclude them during maternity season it’s time to get to work. One of the most simple and common ways to exclude is to use a flexible, mesh netting. Seal off all points of entry with a solid seal except for one where the bats can exit. From this point use the netting over the entry but don’t seal it up. Attach it to create a funnel, which will guide the bats out. Once they have slipped out of the netting they won’t be able to reenter. Once you have all the bats safely out of your attic you can seal off this last point of entry permanently and start the clean-up work.

Other Areas You May Find Bats
Bats can get into your walls, roof or chimney. In these cases you should treat the removal in much the same way as if they were in your attic. There are times they may actually get trapped in the wall and if this happens you are going to have to do your best to locate where in the wall the bat is, create a hole and carefully remove the bat. It is not unusual for a bat to accidently get into your home. When this happens it can be a natural reaction to try chasing the animal out with a racket or a broom. This will only escalate the situation and can cause more problems. You should instead try to open every possible exit for the bat and allow it a chance to escape on its own. If this doesn’t work, or if the bat seems injured, sleepy or sick you will need to be more active in removal. First make sure to keep safety in mind. Wear a pair of thick, leather gloves. Cover the bat with a thick towel by using a netting motion. Gently carry the bat out and lay in grass near a tree or shrub.

What Kind Of Damage Can Bats Cause
Bats aren’t like rodents. They don’t really nest which means they will not tear at insulation, shred wires or chew through wood and pipe. While this may come as a relief it’s important not to underestimate the damage they can do. The biggest problem that comes with bats is the guano. Once it dries it can release toxic fungal spores into the air. The piles of urine and feces can contaminate insulation, rot wood and ruin ceilings. When it comes to bats this is where the damage comes from.

Do Bats Carry Diseases
One of the most common diseases you have to worry about with bats is histoplasmosis as well as rabies. Histoplasmosis is a disease that is caused by breathing in a fungus (Histoplasma Capsulatum). The spores for this fungus can be found in drying and dried bat dung (guano). The infection starts in the lungs and generally hits people who have a weak immune system such as the elderly, already ill or young children. Those that have emphysema, pneumonia, or bronchitis are also particularly prone. If the disease is left untreated it can get far worse. Untreated histoplasmosis can cause the lung infection to spread to organs like the liver and spleen. A person will suffer lung scarring and lasting damage as well as damage to internal organs and blood vessels. Often people with histoplasmosis don’t realize they are suffering from the disease because the symptoms look quite a bit like flu symptoms. In addition to histoplasmosis bats can also carry rabies. Though a bat isn’t an aggressive animal or a top carrier of rabies they can transmit the disease. A bite from a bat can be so small that a child might not realize it’s what happened. The bats may fall through a damaged ceiling and a child accidently come into contact with one, unknowingly becoming infected with the deadly disease. In addition, an adult may not consider the small animal a danger and attempt to remove it by hand. A bat that is out in the daylight, not active or easy to catch can be sick and quite easily with rabies. It’s critical if bitten by a bat that you or your child seeks medical treatment immediately. If the bat has been captured make sure to take it with you so the health department can discover if it is carrying rabies or not.

How To Clean Up The Guano
Once your bats are out the mess they left behind will need to be removed. This is a process that is not only filthy, it can be downright dangerous. If you have the option this is a good time to call in a professional. If not then make sure to wear protective clothing and a very well-made mask. As said before, guano can carry histoplasmosis spores which are very dangerous to your health when breathed in. It’s good to keep the guano damp so less of the spores drift into the air. A light mist of an enzyme-based microbial solvent will help keep the fungal spores from going airborne. If the spray can’t be found then a disinfectant or in a ‘worse-case’ scenario- you can use water for keeping dust and bacteria from travelling into the air so easily. The next step is to shovel the bulk of the waste away and finish by vacuuming up the rest. Tightly bag and seal this waste and toss. If the guano has contaminated the insulation you’ll need to replace this. Clean the area with disinfectant thoroughly. The best way to do this is to use a specially made enzyme-based microbial cleaner that can eliminate organic material. You can also get this in a fogger or mister and it’s a good idea to use a cleaner like this as well.

What Is The Natural Habitat Of Bats
Bats are nocturnal and enjoy roosting in very warm areas. When bats take shelter in a home it is almost always an all-female maternity colony setting up house to have their babies. They only give birth to one baby and this usually takes place in late spring. The pup or kit (name for a baby bat) remains unable to fly till mid to late august. When they can they will choose hollow trees, caves and similar areas for shelters. Often they pick locations near water sources so the insects they feed on are plentiful and so they don’t have to travel far for water. Though they are not blind, their eyesight is very limited especially since they are creatures of the night. Many bats use echolocation to travel and hunt. They have very keen hearing and use a form of sonar to pick up on food and obstacles, helping to guide them through darkness. Bats are very important for the environment because they eat a lot of insects. These can include large populations of disease carrying mosquitoes, beetles, gnats, moths and flies. In fact, some species eat up to half their body weight in insects daily and nursing mothers will eat even more than that. In addition to being important for the environment, bats only have one baby a year and it takes several months before this pup can fly about and be fully mobile. Their fragile ability to reproduce and their importance to the ecosystem is why it’s important that these animals aren’t harmed senselessly and is the reason they are usually protected. The most common species in North America that people may find in a colony on their property are the Little Brown Bat and the Mexican Free-tailed bat.

If Bats Are So Good For The Environment Why Not Leave Them There
If there are bats in your home, then you will want get them out. It is true that they aren’t aggressive and won’t chew up your attic. They will however come back year after year to roost and raise their young. The maternity colony will grow with each passing season and before you know it you could have a colony ranking in the hundreds. Because bats have such a high metabolism and eat so many bugs they pass a lot of waste. This guano will accumulate in your home and can cause health problems as well as structural damage. For this reason you need to get the bats out safely and as quickly as possible. If you want to attract bats to your property and offer them shelter, then by all means do so. There are many different plans for bat houses. They are simple to construct, don’t cost much to build and can be a wonderful way to spend an afternoon teaching children about these lovely creatures. Housing bats on your property is an effective and natural means of insect control. In addition, it can positively impact the environment by offering shelter for these harmless little creatures that are so good for the ecosystem.

Will Repellents Work To Get Rid of Bats in the Attic
There are many different repellents on the market that people will often try when searching for help with the removal of bats. There are some that are sprays and some are pellets. Some are packaged as bat removal products while some people try a wider range repellent. There are even those that will recommend moth balls. In addition, many will suggest peppermint spray or oil as well as ammonia. In truth, none of these repellents will help rid your attic of a bat colony. They are neither strong enough nor are they long-lasting enough to keep bats at bay. They are a waste of money and people shouldn’t try these as an option. What about the lights, sounds and sound emitting devices you can find on the market? There are many different types of electrical devices being sold as bat repellents and the truth to this is that they are generally ineffective as well. You can waste your money on any of a wide range of marketed devices or you can spend your time excluding the bats from your house and insuring they don’t reenter.

What About Poison
Once people find that repellents aren’t going to work for their bat problem they will often turn to trying to use poison. While poison can be very effective in getting rid of any bats in your home that actually eat the poison (bats feed off live insects so nibbling on a block of poison is unlikely) it is one of the worst choices. First, as stated above, the bats are unlikely to actually consume the poison. Second, if they do eat the poison you are going to have to deal with dead bats. Chances are, once you realize you have a bat problem there is a colony in your home which could be as many as forty or more mother bats. Poisoning these bats can fill your attic with dead bodies that will decompose and can expose you to disease and fill your house with stench. In addition to the above reasons one of the biggest reasons to not use poison is the fact it is inhumane. Finally, in almost every state in America there are laws against poisoning these very beneficial animals. Under no circumstances should you consider fumigating or poisoning to remove bats from your home. Exclusion is the more humane method and the only effective method of removing bats from your home.

You're still reading this? Okay then, shoot me an email (see link right below) or better yet, call an expert in your hometown, on my 2014 Directory of Bat Removal Professionals. Good luck, and be smart about getting rid of bats in the attic!

Please be kind to bats! They are valuable animals, not aggressive, and they are vulnerable!
If you have any questions about bats in attics, just email me at david@batsintheattic.org