Bats are mysterious creatures preceded by many fears and misconceptions. With more than 1,400 species worldwide, bats are actually incredibly beneficial to a balanced ecosystem but have been known at times to cause interior pest issues. It can be difficult to pinpoint whether the pest activity you're noticing has been caused by bats. How do you determine if you have bats in your house or not? What if you know for sure that you have bats inside but you can't get rid of them?
Part of the order Chiroptera, bats are not inherently destructive, but their waste is high in uric acid which makes it corrosive; it is also incredibly stinky, especially when it piles up on absorbent interior insulation. When large amounts of corrosive bat waste pile up over time, it can compromise a variety of materials and structures.
Bat droppings carry fungal spores that can cause disease in humans. Bats also carry rabies. While contracting rabies from bats can be rare, it is always better safe than sorry. If you are inspecting for a bat issue and find an accumulation of droppings or a large number of bats, use a respirator, gloves, eye protection, and other Personal Protective Equipment (PPE).
What Do Bats Look Like?
If you can catch a glimpse of them, bats have noticeably scalloped wings and an incredibly distinct way of flying. They are most active at dusk, which can make them difficult to see outside, especially because of their dark coloring. Outside, they are most easily detected by the sounds they make.
There are more than 1,400 bat species worldwide and more than 40 species of bats throughout the United States. When it comes to bats living inside structures, if you live in the U.S. your bat is likely one of three culprits:
- The big brown bat (Eptesicus fuscus)
- The little brown bat (Myotis lucifugus)
- The Mexican free-tailed bat (Tadarida brasiliensis)
Most bats are nocturnal and are not likely to be seen out and about during the day. If you find a bat during the day, do not pick it up, even if it is laying on the ground. This bat could be rabid and/or sickly. By picking it up, you risk being bit and contracting a disease. Call your local animal control or wildlife removal specialist to help the animal.
6 Ways to Get Rid of Bats
Bats are an important part of our environment. They are especially good at controlling unmanageable exterior insect issues. A recent study shows that the number of mosquitoes consumed by bats is even higher than what was once thought. When at all possible, it is encouraged that homeowners find ways to live peacefully with bats. If the bats are in your house, you want to get them out and if they are around your house, you want to find out how to keep them outside where they should be.
Before getting started with bat control, first determine that you're actually dealing with bats. Also research the laws in your area. It is very important to follow local and state laws regarding protected species, and bats are protected in many areas.
Install a One-Way Door
A one-way door is a tool that allows the bat to leave but blocks it from re-entering. These can be incredibly helpful in avoiding a particularly stinky situation. If an entry point is sealed up with a bat or other animal inside and it cannot get out, the animal is likely to die inside, causing a serious smell issue. While this smell should go away on its own in about 1 to 2 weeks, a one way door helps prevent this issue.
Want to save some money on equipment and professional help? Make your own one-way door. Locate the bat entry point and wait until the bat leaves to hunt at night. Once the bat is gone, cover the entry point with a thick, black garbage bag. When the bat returns, it will attempt to use its sonar to enter its roosting area in your attic but will no longer be able to detect the open hole. This will force it to look elsewhere for shelter.
Seal Entry Points
If bats are getting into your attic space or other areas, start by finding where they are entering and sealing it up. Try to let the bats leave before sealing the hole, as this will make sure they don't die inside.
When finding entry points for bats, it is best to perform an interior attic inspection as well as an exterior roof inspection to determine if there are any holes that need to be closed up or roost spots that need to be addressed. Make sure all vents, flashing, and the areas around your chimney are sealed. If you think you've found an entry point, look around the entrance of the hole for greasy residue and discoloration, also called 'grease trails.' This can indicate bats or rodents are entering, so make sure to be thorough with your inspection to determine what you're dealing with.
Reduce Exterior Food and Water Sources
Bats love to eat insects. By making sure your exterior lights are off at night, this will help reduce the surrounding insect population and can help reduce bat activity. Bats are also attracted to bird nectar feeders and standing water they can use to get a drink. Reduce these attractants, and you will reduce the chances of a bat setting up camp on your property.
Hang a Bat Box
There's no denying how beneficial bats can be, especially when it comes to reducing insects such as mosquitoes. It may seem contrary to your goal of getting rid of bats, but once you seal the bats out of your attic space, consider building or purchasing a bat box (or five!) for your bat friends. You can reap the benefits of a smaller nuisance insect population and the surrounding bats will be less likely to try and enter your home when they have such a favorable spot available to them.
Use Bat Repellents
There are a number of bat repellents on the market including essential oil pouches and ultrasonic devices. Repellent solutions can be hit or miss. Know that these solutions can involve a lot of work and money with varied results. When possible, it is recommended that you keep the bats around and focus primarily on sealing them out of interior spaces, not using repellents.
Signs of Bats in Your House
If you happen to have a bat flying around your living space all of a sudden, quickly open the doors and windows to help direct the bat outside. The bat is likely young and did not mean to enter your living space. It just wants to make its way outdoors, where it will spend its time hunting nuisance insects such as mosquitoes.
If you suspect bats are roosting (hanging out) in your home, there are a number of indications to look for. When inspecting for bat activity, keep your eyes and ears open for the following:
- Visual confirmation of bats leaving your house at dusk (typically from the eaves, roof or attic)
- Interior sounds such as scratching or squeaking inside the attic space
- Exterior sounds, particularly small, high-pitched chirping sounds right around sunset
- Accumulation of droppings inside and outside, especially underneath suspected hang-out spots
- Stains and a distinctly strong odor inside, especially in and around attic insulation
Unfortunately, many signs of bat activity are similar to those of other pests such as rodents, birds, and other wildlife. Unless you see the pest itself, thorough inspection will likely be needed in order to confirm which pest you are dealing with.
Droppings can tell us a lot about an animal. Bat droppings are commonly confused with rodent droppings, especially those of mice. Did you find droppings? If you can't tell whether you're dealing with bats or rodents but you're determined to find out, grab a pair of disposable gloves, pick up a dropping sample, and inspect it. Bat and mouse droppings are smaller than a tic tac mint. Do its edges look rough? It could belong to a bat. Now, if you're up for it, squish it between your fingertips. If it crumbles between your fingers, it is a bat dropping, but if it squishes flat like a pancake, it likely belongs to a mouse or juvenile rat.
Inspecting for Bats Around Your House
First, park a chair outside your home right around dusk. Sit and listen for the classic, high-pitched squeaking noise bats make while using their echo-location to hunt. If bats are around, you can often see them swooping around in the twilight while they seek out insects. Watch for them leaving from your roof, attic, or eaves. If you see bats leaving your house, be prepared to perform a thorough inspection or find a local Integrated Pest Management Specialist to help.
If you're going to attempt your own bat inspection, make sure you're prepared for what it will entail.
To perform a bat inspection, you will need:
- Proper PPE
- A good quality headlamp or flashlight that clips to a hat, leaving your hands free for climbing
- A ladder
It may sound silly, but you're also going to need some confidence in your abilities. After all, you must be safe at all times. While performing your inspection, it is very unlikely that you will be mauled by some sort of wildlife, but you will be on a ladder, and you must understand that if you're looking for bats you very well might find them ... or possibly something else.
Be honest with yourself: Do you spook easily? Could you fall off your ladder? Are you afraid of small spaces? If you are not comfortable with bats and critters, ladders/heights, or small spaces, that's OK, but it may be best to get some help from a family member, friend, or pro.
If you determine you have a bat issue, be sure to read up on your local and state laws regarding bat control. In many places bats are legally a protected species and it is incredibly important to be aware of the legal restrictions and requirements in your area before carrying out any DIY pest control.
What Causes Bats in a House?
When it comes to managing pests of any kind, consider what conducive conditions are present around your home. A conducive condition is simply any environmental factor that could be attracting the pest (in this case, bats) to your property. Find what conducive conditions are drawing the bats to your home and manipulate those factors to make the environment around your property less desirable to the bats.
Conducive conditions to consider:
- Water sources: Do you have a fountain, pond, or regularly timed irrigation system that is providing them with water?
- Food sources: Bats love insects. Are there attractants around your home, such as standing water or exterior lighting at night, that are drawing insects in?
- Harborage areas: Where are they seeking shelter? Where do they hide during the day?
If you have noticed a consistent bat problem inside your house, could your roof be the problem? Tile roofs, especially certain styles, provide gaps beneath the tiles that provide warmth and can invite bats right in.
When to Call a Pro
If you are dealing with a severe bat issue, don't be afraid to call a professional IPM specialist, especially if extensive clean-up is needed. A pro can also help if you are wary of heights or creepy critters.
Bat Droppings and Urine. 2021 Bat Conservation Trust.
Histoplasmosis: A Common Fungal Lung Infection. Centers for Disease Control and Prevention.
Human Rabies Prevention Program. Oregon State University.
Coming in contact with bats. Centers for Disease Control and Prevention.
Wray, Amy K. Incidence and taxonomic richness of mosquitoes in the diets of little brown and big brown bats. Journal of Mammalogy, vol. 99, no. 3, pp. 668–674, 2018. doi:/10.1093/jmammal/gyy044
Acceptable Management Practices for Bat Control Activities in Structures A Guide for Nuisance Wildlife Control Operators. U.S. Fish and Wildlife Service.