Many people have a great fear of bats. After all, they are mysterious, scary looking and can transmit rabies. If that’s not enough, we also watch scary movies about blood-sucking vampires to increase our fear of bats. The good news is that vampires are not real, however, vampire bats are quite real, and they do suck blood from humans. With that said bats are still quite misunderstood and they are considered to be an essential part of our ecosystem. Here is everything you need to know about them, and the best way to get rid of bats when they become a pest.
Bats have a very unique skeleton and are among the most diverse vertebrate groups in the animal kingdom.
With more than 1300 species (Fenton and Simmons, 2014), bats make up a fifth of all mammals on the planet.
Although bats vary in size and color, they all belong to the mammal order Chiroptera, which means “hand-wing.” and are the only mammals that can truly fly.
As with other mammals, bats are warm-blooded, covered with hair and give birth to live “pups” that drink milk from their mothers.
A few species feed on animals other than insects; for example, the vampire bats feed on blood.
Most microbats tend to be nocturnal and are using a complex system of sound vibrations called echolocation which allows them to determine distance, speed, and even identification of prey in total darkness.
What Do Bats Look Like?
Bats are usually described as looking like a rodent with wings. A bats wing is similar to a human hand. Instead of a thumb, they have a strong claw that they use for grabbing and climbing.
The rest of the long fingers are attached by a thin layer of skin or wing membrane that stretches between each finger of the hand all the way to the leg which allows them to fly.
Bats have very strong claws on their feet that allow them to hold on to just about any structure and hang from it. Bats can vary greatly in size and color.
Below are some examples of bats:
- Size: 6 Inches to 6 feet wingspans
- Weight: 2 grams to 4 pounds
- Lifespan: as long as 30 years
What Is A Bats Lifecycle?
Females will roost to give birth to young usually in a cave, tree, abandon building or attic space.
An adult female bat will usually only have one pup during a birthing period and may give birth up to three times per year.
Bats mate in the fall and winter, giving birth around mid-April to July.
A newborn will nurse until its wings are developed enough for flight usually 3 to 6 weeks and will be weaned from its mother’s milk by mid-August.
Baby bats have a very high mortality rate, but if they can make it to adulthood, they can live a long life, as long as 30 years or more.
Why Are Bats Important?
According to the United States Geological Survey, bats save the U.S. agriculture billions of dollars per year in pest control.
In many tropical environments, some plants rely entirely on bats for pollination.
Because of these important roles bats provide, they are considered to be a “Keystone Species”.
Without keystone species, the ecosystem would be dramatically different or may cease to exist altogether.
What Does A Bat Eat?
Bats have very sharp teeth to puncture with and eat a wide variety of insects such as crickets, grasshoppers, beetles, moths, mosquitoes, small fish, frogs, and lizards.
Some bats will even eat scorpions and poisonous centipedes such as the Pallid bat from the Arizona desert which is immune to their poison.
A Spectral bat from Costa Rica is a large bat, with a wingspan of nearly three feet that is a carnivore feeding on a wide variety of small vertebrates, including rats, birds and small opossums.
In Addition, bats are well-known for eating fruits and vegetables.
The Greater Short-Nosed Fruit Bat is known as a major pollinator and seed disperser for a wide variety of plants in Thailand and The Flying Fox is one of the largest bats from Australia.
Check out this video of a Flying Fox enjoying a mango.
According to a document on the US Forest Service Website, scientists have discovered that some small bats can catch up to 1,000 or more small insects in a single hour. A nursing mother bat can eat more than 4,000 insects in a night.
What is the Behavior of a bat?
Most bats are nocturnal, which means they like to come out from dusk till dawn.
They also like to live in colonies, usually in caves and trees, but sometimes will roost in attics, soffits, louvers, chimneys, porches, under siding, eaves, roof tiles or shingles and behind shutters.
At dusk, bats will emerge from their roost in search of food when insects are plentiful.
Bats will return to the roost a dawn to get protection from predators and raise their young.
How Do Bats Get Into Attic Space?
Bats echolocation provides them with an amazing ability to find small holes or gaps on a roof space or under eaves.
They can squeeze through very gaps as small as 1/2 of an inch. Once they find a place to enter, they will start roosting to raise their pups.
Attic spaces or under a barrel tile roof are a perfect place for bats to raise young providing them with protection from predators and a quiet, warm, dark environment.
Some of the most common bats in North America that will roost in attics are the little brown bat, the big brown bat, and Mexican freetail bats.
How Do Bats Damage Property?
A bat colony will frequently return year after year to the same roost often going unnoticed until the colony has grown quite large.
When colonies get larger, they create significant damage due to the waste they produce.
Bat feces called guano, and urine is very toxic and has a foul ammonia-like smell that will corrode a roof or other parts of the structure causing significant damage.
Do Bats Transmit Harmful Diseases?
Bats are known to carry dangerous diseases that are a serious threat to our health. Bats transmit diseases such as rabies, SARS, Ebola, Coronavirus, and many other flu-like viruses through direct or in-direct contact.
Zoonotic diseases from bats have increasingly been a serious concern in the scientific community.
In an article, on the American Veterinary Medical Association website, Doctor Gerald T. Keusch, MD, a professor of medicine and international health at Boston University said bats are a “largely unknown, underinvestigated, poorly understood, and now-definitive vectors for new emerging viruses.”
THIS IS NOT A JOKE.
Is Bat Guano Dangerous?
Although bat guano is actually harvested as a resource for fertilizer, it carries a fungus that causes an infection called Histoplasmosis.
Histoplasmosis is transmitted when spores become airborne, often during cleanup of dried feces.
Make sure you do not disturb the ground where guano droppings are found.
If you are cleaning guano, be sure to spray the area with a virucide disinfectant sanitizer to kill bacteria, viruses or mold spores before cleaning the guano.
You can find a good virucide disinfectant sanitizer on Amazon.com
How To Know If You Have A Bat Problem?
Unfortunately, signs of a bat infestation are not always noticeable until the colony becomes very large.
Bat colonies usually start out with just a few mating pairs and can go unnoticed for years before it becomes obvious.
1) Look For Brownish Stains Near Entry and Exit Points.
When bats enter and exit a crack or hole, they will leave brown colored stains or rub marks from body oil that build up over time, which can sometimes be mistaken for mold or mildew.
If under a barrel tile roof, the build-up of guano and urine will leave additional brownish stains, usually streaking down the sides of the structure.
2) Look For Bat Guano and A Heavy Ammonia Smell.
If in your attic, bats will leave piles of guano dropping under the roosting site.
Bat feces has an ammonia-like smell that gets very strong.
As a colony becomes larger, fifty to several hundred, the air quality can become very bad, to the point where it is not safe to breathe.
3) Look For Bats Exiting At Dusk.
At dusk try to observe bats leaving your roof or attic right before dark.
As they start to exit, bats will make very low chirping sounds that sound like very faint tweets.
You may also hear scratching sounds from their sharp claws as they crawl to the exit points.
Check out the video below as an example of bats exiting a barrel style roof.
4) Look For Bats Entering At Dawn.
At dawn, right before daylight, sometimes referred to as the twilight, bats will be returning to the roost from a night of feeding.
They are easier to spot at dawn since they return together in larger quantities to take shelter before daylight.
They will swarm around until they can find an entry hole and then disappear into roost. Below is video footage I took of a bat infestation returning a dawn.
If you start to suspect bats, you should try to inspect the outside of your home for several days at dawn and dusk, making notes of where they are coming and going.
This information will be helpful when you start the exclusion process.
Bring a flashlight with you and try to take video footage while walking around your home for playback later to help locate bat entry and exit points.
The Bat Removal Process
At this point, you probably have identified several indicators letting you know that you have bats living in your attic, roof or other parts of your home.
It’s time to learn the step by step process to Bat Exclusion which is the most permanent and humane way to get rid of bats.
The process is not difficult, but you will need to follow certain guidelines to be successful and to do it lawfully.
DIY Bat Exclusion; A 10 Step Process:
- Check your local laws for bat removal.
- Observe your house at dawn and dusk to find exact entry and exit points.
- Inspect inside your attic.
- Try to identify which species of bats you have.
- Inspect the entry holes – look for gaps as small as 1/2″.
- Seal all exterior gaps not currently used by bats.
- Install one-way exclusion devices on the main entry/exit areas.
- Keep an observation for 5-7 nights.
- Once all bats are gone, remove the exclusion devices and seal the holes.
- Start the cleanup process.
1. Check Your Local Laws For Bat Removal.
Bats, in general, are a protected species in every US state which means it may be unlawful to kill them or interrupt hibernation and mating periods even if they pose a health risk.
Check with your state fish and wildlife office for your local laws on bat exclusion as you may have to wait till the maternity or hibernation period is over.
In North America, the maternity season begins around April and ends by late August.
Some states may allow exclusion during maternity periods but only by a licensed wildlife control operator.
In Florida for example, exclusions are illegal between April,15 and August,15 by anyone and it is also illegal to use poisons on bats as well.
You will have to wait for the maternity period to end before eviction begins, but there are still things you can do to prepare for the exclusion.
2. Observe your house at dawn and dusk to find exact entry and exit points.
Start gathering intelligence on the bats to find out when and where they are entering and leaving your home.
Make sure you bring a flashlight, and a cell phone to take video of the bat’s activity at dawn and dusk to take note of the main entry points.
Do this for several days leading up to the time you can legally evict the bats.
Don’t forget to bring bug spray with you so you can stay outside longer to observe the bats.
Be patient when doing this process, since you may have to wait until it is almost dark at dusk.
You can check on where the bats enter at dawn as well. The more information you collect the more successful you will be.
I suggest you observe each side of your home to ensure you find all the entry points. You may have to do this for several days to really get a good idea for the bat’s behavior.
3. Inspect inside your attic.
You will need to get into your attic to find the roosting locations to help find the entry and exit points.
Look for areas where their droppings have accumulated. They will be roosting right above that location.
This will also help to identify the cleanup locations for later after the bats are gone.
Make sure you wear protective clothing including gloves, long sleeve shirts and pants, a hat, safety glasses, and a respirator mask.
Look for any holes or gaps that may lead into your living space and seal them off.
Do this before starting to seal any external openings to prevent bats from getting into your living area.
4. Try to identify which species of bats you have.
You may be asking if my goal is to evict the bats, does it really matter if I know what kind of bat is in my attic.
The short answer is not really, however knowing the species can help to understand their behavior.
If it is a migrating type of bat, then they usually leave on their own.
Instead of setting up one-way exclusion doors, you can wait till they leave and then just seal all the openings so they cannot get back in the next season.
Make sure you inspect and observe at dawn and dusk to know for sure that they have left before sealing the main entry points.
For a good list of bat species, check out Bat Conservation International at batcon.org.
5. Inspect the entry holes – look for gaps as small as 1/2″.
Get on a ladder and take a closer look at the entry points. Find the ones that are the main entry points you observed the bats exiting at dusk.
The main entry/exit point will be where you will install your one-way devices.
Inspect the rest of the area around for other potential entry points that do not look like they are using and prepare to close them off.
6. Seal all exterior gaps not currently used by bats.
Use caulking, metal flashing, screening or heavy-duty mesh to seal any openings on the outside of your home where bats can use as a secondary entry point.
This step is crucial to your success, and remember to seal only the holes that bats are not currently using as entry/exit point to prevent them from getting back into the attic after the eviction process has started.
Use a water-based caulk and apply it earlier in the day to ensure it has time to dry before bats emerge in the evening.
If there are many secondary entry holes, you may have to close the holes over several days before starting the eviction process.
7. Install one-way exclusion devices on the entry/exit areas.
When starting the exclusion step it is important to remember that bats do not leave the roost all at the same time and may not exit during bad weather especially if it is raining.
It will be necessary to install one-way exclusion devices at all of the main entry/exit points allowing the bats to exit the space and not able to return.
Bats can be excluded using tubes and netting. Put the exclusion devices in place during the day before the bats have exited the space.
Using Tubes To Exclude Bats
Tubes work well in most situations to allow bats to exit.
A tube should be at least 2 inches in diameter and about 10 inches in length.
The smooth surface of the tube prevents bats from being able to cling to the inside.
Place the tube no more than 1/4 inch into the hole ensuring bats will be able to climb over the ridge to exit out of the tube.
Placing a collapsible plastic sleeve over the end of the tube will prevent the bats from entering back through the tube.
You can make your own tubes with some PVC pipe or an old caulk tube as long as it has been completely cleaned out and both ends have been cut.
If you would prefer to purchase one specifically designed for bat exclusion the Batcone on Amazon.com is a good choice.
Using Netting To Exclude Bats
Sometimes a tube is not the best option on some entry/exit points for exclusion.
Entry/Exit holes on vertical surfaces such as louvers, shingles or under a window frame may require netting to be placed to allow bats to slide down and out but preventing them from getting back in the opening.
The flexible plastic mesh netting should be 1/6 inch or smaller and made from Polypropylene.
The polypropylene allows the bat to easily slide down along the mesh and the 1/6 inch openings are small enough to prevent the bat from getting stuck.
The only downside is the mesh can be a bit expensive. However, if you consider that hiring a Bat Exclusion Company to do this work will cost you hundreds or even thousands of dollars then it is well worth the cost to use the right material.
Here is a link for 1/6 inch Polypropylene Beetle Netting on Amazon.com.
8. Keep An Observation On Your Exclusion Progress for 5-7 nights.
Keep exclusion tubes and netting in place for 5 to 7 days to ensure all bats have exited the space.
Observe the bats exiting at dusk from the one-way tubes or screening.
If you do not see any bats exiting, ensure you have installed them properly. Do this during the daytime to prevent coming in contact with the bats.
Also, observe the bats returning at dawn to ensure the bats are not getting back in through other holes.
9. Once all bats are gone, remove the exclusion devices and seal the holes.
After all of the bats have been evicted from the attic space, seal the exit holes permanently to ensure they cannot return.
With all the holes shut the bats should not be able to enter the roof or attic space.
Continue to monitor at dusk and dawn for bat activity.
If you are sure they are completely evicted then you can begin the cleanup process.
10. Start the cleanup process.
As you know by now, bat guano and urine is toxic and can carry bacteria that can make you sick.
It is important you talk precautions when cleaning to ensure you do breath in any of the viruses, bacteria or mold.
Your first step is to ensure you are wearing all the necessary safety devices such as gloves, long sleeves, pants, a hat, safety glasses, and a respirator mask.
Next, you’ll want to spray a virucide disinfectant on the area to kill any viruses, bacteria or mold spores before moving any of the infested material.
I recommend Nisus DSV Disinfectant sanitizer virucide on Amazon.com. This is professional grade stuff.
Spray the area thoroughly before moving the guano infested material.
Wait about 10 minutes before shoveling or picking up the mess placing it into a heavy-duty plastic garbage bag.
Do not use a vacuum to prevent the particles from becoming airborne, which will increase the chances of bad stuff being inhaled by you and your family.
After picking up the area, spray the DSV once again to completely disinfect everything.
Congratulations! You have just saved yourself thousands of dollars doing a permanent and humane bat exclusion yourself.
Bats are very exciting and misunderstood creatures.
They are beneficial to our environment in so many ways and for that reason, they are considered a Keystone species.
We should never harm a bat since they are so special, however, as with most wild animals we need to protect ourselves when they pose a danger to our family and property.
Using proven bat exclusion techniques we can do our part to protect bats and preserve the species.
You may also want to consider putting up a bat house to give them an alternative place to roost in your area. This may deter them from you home and help them thrive at the same time.
Check out my post on How to Get Bats in a Bat House for more information on bats and bat houses.
Let’s all show them the respect they deserve.