Bat Information

Bats belong to the order Chiroptera (which literately means “hand winged”) and are the only mammals that truly fly. There are about 900 species of bats worldwide, second in number only to rodents. There are 10 species of bats in Maryland: 3 of them migrate in the colder months and 6 hibernate in tree cavities, attics, and other structures.

Migrating Species

Hibernating Species

Habitat and Roosting Habits

Some species of bats such as Big Brown Bats and Little Brown Bats congregate in groups called colonies. Other species such as Eastern Red Bats prefer solitary lifestyle. Most solitary bat species roost in natural structures like hollow trees, caves, rock crevices or under tree bark. However, they are occasionally found in man-made structures during migration. Most colonizing bat species will roost in man-made structures such as attics, behind shutters, under shingles, eves, in chimneys, barns, under bridges or any other suitable roosting site.

Bats sometimes have two roosting sites within the same structure or within two different structures that are close to each other. One roosting site can be located in the area of the attic that has the highest temperature for hibernation (the sunny side). The other roosting site can be located in an area that has a cooler temperature (to cool off in summer).

Diseases & Parasites of Maryland Bats

Bat Bugs vs. Bed Bugs

Bat bugs and bed bugs are blood-sucking insects that feed on bats, birds, humans and any other warm-blooded mammals they come across. A bat bug is a very close relative of a bed bug. The two species look so much alike that a microscope is needed to tell them apart. Bat bugs used to inhabit Maryland homes long before bed bugs became reintroduced to the U.S.

Bat bugs are found in homes and buildings infested with bats. But once the bats are gone, they can find their way in and start feeding on people. The Big Brown Bat and the Little Brown Bat are particularly guilty of spreading bat bugs because they roost in large numbers and are the two most common bat species in Maryland. Typically, bats do not host bed bugs, even though the two species are so similar. However, since the resurgence of bed bugs in the past decade, there have been many documented cases where bed bugs have been found on bats.

Both bat bugs and bed bugs are very difficult to control and require all infested sites to be effectively treated by a professional pest control company. The first step in bat bug control is always bat removal. Thankfully, unlike bed bugs, bat bugs can’t survive for a long period of time or reproduce without a bat host.


Histoplasmosis is a lung disease caused by a microscopic fungus, histoplasma. It exists in nature without harming anyone, but having it in your home is dangerous. This mold grows in environments that offer high nitrogen content, which can be found in bat droppings (guano). Large amounts of guano slowly decomposing in your attic create perfect conditions for histoplasma.

You can contract this disease by simply visiting the site where bats roost and inhaling the mold spores. If you have bats roosting in your attic, it is highly recommended that you have professionals perform an attic cleanout immediately after the bats are evicted. The soiled insulation should be removed with a TAP Vac system that is specifically designed for this purpose. After the soiled insulation is removed, all remaining guano should also be cleaned out with the TAP Vac system. Once your attic is free of guano, a sanitizer and disinfectant should be applied to the area before new insulation is put down.


Like all mammals, bats are susceptible to rabies, but only a small percentage of them carries the disease. The only way to truly identify a bat with rabies is through laboratory testing. As for the visual cues, look out for erratic and uncharacteristic behaviors, such as flying during the day time, flying into buildings or structures and landing on the ground. 75% of all bats found on the ground test positive for rabies and 17% of animals in the United States that test positive for rabies are bats.

Most of the human rabies cases in the United States are caused by bats. People can’t get rabies just from seeing a bat, having contact with bat guano, or from touching a bat on its fur—there has to be a bite. Usually people know when they have been bitten by a bat, but because the bat’s small teeth leave tiny marks, bites suffered by a sleeping person may go unnoticed. If you wake up and find a bat flying around in your bedroom or in a room with an unattended child, you should immediately inspect the body and seek medical attention. If you have been bitten by a bat, attempt to capture it and take it to your local Health Department to be tested for rabies. Be sure to wear protective gloves and use a container with a tight-fitted lid. Never grab a bat with your bare hands!

Why Do Bats Move Into Buildings?

Over the past few hundred years, humans have eliminated much of the bats’ natural habitat and replaced it with buildings, bridges and other man-made structures. Like many other species, bats have adapted very well to their human surroundings and have learned to flourish in them. Attics and bridges have taken the place of caves, hollow trees and rock crevices as roosting sites for bats. In many cases, man-made structures offer bats much better protection from weather and predators than nature ever could. Attics are at the perfect height and provide the perfect temperatures for roosting bats, especially for maternity colonies. During the extreme heat of the summer bats will sometimes work their way down from the attic into interior walls where the temperature may be a few degrees cooler.

Bats are attracted to some areas more than others. If you live near a body of water, you are more likely to have a nuisance bat problem at some time or another. Bats like to stay close to a good food source such as mosquitoes, which are abundant around water. We recommend having your attic space inspected by a professional every 2 to 5 years as a preventative measure.

How do Bats Get In?

Attics may seem impenetrable, but keep in mind that bats only need a ¼” opening to enter an attic. Most attics do have some gaps and holes along the roofline, drip edge, fascia boards and soffits, as well as vents that might not be tightly fitted. Bats will also enter attics through the ridge vents on the peak of the rooftop. Therefore, bats can easily gain access to most attic spaces.

If they can’t get into the attic, bats will roost under loose shingles or under siding. They can also roost in gaps behind chimneys if a chimney has shifted and become separated from the main structure of the house. Bats will roost in chimneys and flues that do not have animal-proof caps and covers on the top. Porch roofs and awnings are another place where bats like to roost. Bats do not chew or gnaw on any type of structure to gain access; they only use pre-existing gaps and openings.

How to Get Rid of Bats

If you want to remove bats from your attic, be sure to hire a trusted bat removal company. Each state has different laws and rules regarding bast eviction from a home or a building. Mid-Atlantic Wildlife Control abides by all state and federal laws during both the inspection and the eviction. Bats are protected by law in every state and can only be evicted by using special eviction devices and techniques. It is against the law to remove bats by physically putting your hands on them (unless a bat is flying around in your living space), by killing them or by using pesticides.

It is never a good idea to perform bat eviction if you don’t know what you are doing. In many cases, when homeowners have attempted to evict bats themselves, there have been disastrous outcomes such as hundreds of dead bats in attics, crawl spaces or walls, creating an unbearable odor for many months. In other cases, homeowners had to receive rabies vaccinations due to potential exposure to rabies.

Mid-Atlantic Wildlife Control uses superior techniques that remove bats from your home and keep them out. Our technicians will conduct a thorough inspection to locate all entry points that bats are using to access your home. Our technicians also conduct a full inspection of the attic area to locate where the bats are roosting, and any accumulated bat guano. Once the technician completes the attic inspection, they inspect the fascia boards, soffits, vent covers, drip edges and any other vulnerable areas. After the inspection is complete, the technician will review with you what they discovered and what needs to be done to resolve your nuisance bat problem.

Bat Guano Cleanup

Below is a photo of a large amount of bat guano in a child’s bedroom in Jarrettsville, Maryland.

The occupants of this home noticed bats flying out of their fascia board every night and called Mid-Atlantic Wildlife Control for an inspection. During the inspection, the technician heard a noise coming from behind the finished walls in the attic that was converted into a child’s bedroom. The technician drilled a 1 inch round hole in the wall, inserted an inspection camera and discovered hundreds of Big Brown Bats roosting there. After the eviction process of the bat colony was complete, the guano cleanup process began. The technicians ripped down the finished walls of the attic bedroom and removed 2 tons of bat guano that was in the void between the bedroom ceiling and roof. They also removed a large amount of bat guano from the area between the exterior and interior walls.

Do you suspect that attic noise or odor could be attributed to bats? Contact us today for an inspection!