How To Get Rid Of Bats In Attic Vent

Tri-cities Bat Removal

People ask if we can relocate the bats in their attic. Bats cannot be relocated. I think that there is a good chance that if a bat were relocated from one end or our region to another (say from Abingdon to Johnson City) it might still come back. Bats are very attached to their roost site and are highly mobile and excellent at finding their way back home. They spend thousands of hours in the air and have excellent "road maps" in their heads. Bats are also migratory. This means that bats move from feeding/birthing areas to winter hibernation areas seasonally. If a bat can find its way from one cave to another back to your home year after year, the odds are very good that it will wind up back to your home once it is released.

Removing Bats by Exclusion

In our area, the best way to remove bats is by adding a one way door over their exit point. However, the secret to success is understanding bat psychology. Bats consider your house to be theirs. If someone locked the front door to your house would you just go away. No way! You would crawl through the back window or do whatever you had to so that you could get back inside. Well that is exactly what your bats will do.

Seal the entire house not just a point

Done right, bat removal is a "total house" process. Every single potential entrance has to be sealed. Adding the one way door over an entrance will only push the bats to a new entry point on the house. You want to have that entry point sealed and have run a one way door on it so that you don't end up chasing the bats around the house from point to point.

Bats Living in Attics

In late summer the core of our work is bat-proofing homes. In the spring, bats return from hibernation to form maternity colonies. Bats, when they are ready to give birth, are looking for a location where their babies will be secure and will be able to stay warm at night. Attics provide just that and maternity colonies will stay in an attic until Fall when it is time to hibernate. Maternity colonies use the same site every year and are extremely dependable about returning. This year our largest colony had about 75 individuals and 20 - 35 individuals is common. Individuals and small clusters may also be encountered hanging under eaves on the exterior of the home.

This is a young of the year bat hanging on a wall outside its roost in the Johnson City area.

In the wild, bats will roost under exfoliating bark of trees. I suspect that the louvers on attic vents resemble the exfoliating bark plates favored by bats in the wild. Gable vents are a very common entry point for bats. Bat colonies can be found living on the exterior of attic vents or they may get past the vent and live inside the attic. A vent issue is one of the most common scenarios found when inspecting customers' homes. I suspect that, female bats find the warm air currents coming out of these vents appealing and find shelter under the louvers. Bats do not make a great deal of noise and often are missed by home owners until an individual bat wanders down into the living area of the home, a repairman enters the attic, or large numbers of bats are seen exiting the attic. By this time, quantities of guano can accumulate. Homeowners often go for years never knowing that a colony of bats is living right inside of their home. This is one reason that I encourage my customers to have yearly inspections. If you would like to schedule an inspection, please give us a call.

This was an entry point on an Abingdon area bat job. The brown Smear is body oil and dirt. It marks the bat entry point. The white globs are silicone caulk put there by a pest control company that sealed the bats inside the customer's home before … — This was an entry point on an Abingdon area bat job. The brown Smear is body oil and dirt. It marks the bat entry point. The white globs are silicone caulk put there by a pest control company that sealed the bats inside the customer's home before we were called. Sadly, this was done by a well known pest control company.

Bat Entry Points

Bats prefer to enter buildings at their highest possible point. This makes bat work risky and often requires special equipment like lifts. I tell customers that if bats would stay closer to the ground the work would be a lot easier and cheaper.

Bat entry points may be very subtle and may not be noticed by untrained eyes. This is problematic, because without sealing all the entry points, exclusion will not be complete. There may not be any clue visible on the exterior that bats are present but, with increases in the number of bats and an increase in the time that they inhabit a structure, their presence becomes more noticeable. Brown body smears may not be as evident if the background color is brown or another non-contrasting color. Brown smears will not be present if the entrance has low traffic or has only been used for a short time.

Bats inside the house

A bat inside the house in living spaces is a common call that we receive. This type of call can come at about anytime during the year; but it is much more common in late summer. At that point, juveniles that have been just hanging out quietly in attic areas become much more "adventuresome" and start to move about. When this happens, they sometimes take a "wrong turn" and end up in living spaces. Adult bats probably occasionally "explore" their environment and end up in living spaces too; but the timing of most of these calls seems to back up the concept that most are juveniles. I tell customers that "juvenile bats are a lot like teenagers. They don't do what mom tells them and they get into trouble". Undoubtedly, bats do occasionally fly into living spaces through open doors and windows. But, in my experience,if someone reports a bat circling the living room or other space of the home, it is a sure sign that they have bats roosting somewhere in the home. If it is in the summer, they are probably in the attic. If it is winter they are more likely to be in the lower half of the house. If you have this, it is time for a home inspection and possibly a bat watch.

Some homeowners go for years and develop huge colonies of bats and never have a bat enter the living spaces. Other homes have very small colonies of bats and have semi-regular visitors. I believe that the cause of this is often differences in the "geography" of the interior of walls and ceilings. A hole located in the right spot with light on the other side or a draft pulling through it will provide a false escape route to the bat and can bring them into living spaces. A good example of this was in a home I once inspected in the Chilhowie area. This home had very few bats. This home had little guano and probably only had one or two bats that were "occasional visitors"; but it had bats showing up twice a summer on average. During the inspection, I found that this home had a small hole cut through the floor of the attic for electrical lines. This hole was located just under the primary roost site. Any bat that happened to fall and land near this hole was likely to end up finding its way down this hole and into living spaces. On the other hand, other homes that I have inspected have colonies of 50 to 75 and rarely, if ever, have visitors.

Screening corroded by excrement with feces pellets trickling through.

A bat in the living space is a common call that we receive. This type of call can come at about anytime during the year; but it is much more common in late summer. At that point, juveniles that have been just hanging out quietly in attic areas become much more "adventuresome" and start to move about. When this happens, they sometimes take a "wrong turn" and end up in living spaces. Adult bats probably occasionally "explore" their environment and end up in living spaces too; but the timing of most of these calls seems to back up the concept that most are juveniles. I tell customers that "juvenile bats are a lot like teenagers. They don't do what mom tells them and they get into trouble". Undoubtedly, bats do occasionally fly into living spaces through open doors and windows. But, in my experience,if someone reports a bat circling the living room or other space of the home, it is a sure sign that they have bats roosting somewhere in the home. If it is in the summer, they are probably in the attic. If it is winter they are more likely to be in the lower half of the house. If you have this, it is time for a home inspection and possibly a bat watch.

Rabies Transmission

The rabies transmission rate is very low in the United States primarily because of high rates of vaccination among domestic pets. Other less developed countries, where vaccination programs do not exist have much more of a problem with rabies. Authorities in the United States also make active efforts to monitor, manage, and control rabies in wild animal populations that tend to have trouble with this disease. But, in spite of these efforts rabies does occasionally show up. Of people who show symptoms and eventually die in the U.S., bats are more likely to be the cause than other species. This is because bats exhibit what is referred to as a "friendly form" of rabies. Rabid bats are more likely to inflict a small, sometimes undetectable bite on a person who is sleeping, drunk, or in the case of small children, unable to relate to others what just happened. Because of this factor, medical professionals recommend taking prophylactic vaccinations if there is any doubt that a person may have been bitten or in contact with an infected animal.

Rabies is a very serious disease. Rabies is a disease that, if left untreated or is not treated promptly, is fatal. Rabies can be transmitted by bats and bats can transmit rabies to people. The CDC states that:

Bats can transmit rabies through seemingly unimportant wounds.
Bats should not be handled by unvaccinated persons.
Persons who have been in a room with a bat and cannot be absolutely positive that a bite didn't occur should consider prophylactic treatment if the bat cannot be tested.
If there is a possible contact between a bat a person and the possibility of transmission exist, the bat should be saved for testing.

If you have had contact with a bat and there is a possibility that you have been exposed to rabies you should contact your physician or your local health department.

Histoplasmosis

Histoplasmosis is another disease risk associated with bats roosting in a building. Bat colonies can produce large quantities of droppings called guano. Disturbing the guano can create clouds of dust that are then inhaled. Histoplasmosis is a fungal infection of the lungs that results from these particles. Histoplasmosis scars the lungs; and physicians can see these scars on X-rays. According to the CDC anyone can contract this disease; and many people contract Histoplasmosis and recover. Histoplasmosis is most dangerous to persons with compromised immune systems. Of people who check into hospitals, there is a 5 to 8 percent chance of mortality. This mortality, obviously, does not include people who recover from the disease without hospitalization, and so, is probably high.

Guano pile accumulated on a roof under a soffit.

Guano accumulated under a soffit entry point.

Roost sites

Bats are very dedicated to their roost site and will return year after year. Not only are they dedicated to a specific building they also tend to return to the same spot or spots in the building over and over. Thick blankets of guano develop under roost sites. If the roost sites have been utilized for a long period of time they can also develop crystalized urine stalactites. In the photo above crystalized urine appears as amber colored deposits on a vent screen. Acids in the waste often corrode the screen on which the bats were hanging if it is aluminum. Once the screen degrades, bats can access the interior of the attic.

As time progresses, larger waste deposits can develop. Generally speaking, the volume of guano varies depending on the amount of time bats have been present and the number of bats. Small colonies can have the equivalent of a teacup of droppings while larger ones literally have truckloads of guano. Guano will often be concentrated in small "volcano" shaped piles, but will also be scattered about the attic if spaces are large enough to fly through easily.

Waste accumulation

Often, bats decide to roost in exterior walls or in the layers of a roof. If this is the case, guano may not be visible in attic spaces. Guano will still be present; but it is just not visible in the attic. In these cases, removal of guano might be impossible without tearing out walls or removing roofing. Deposits such as this may be encountered later during construction or renovations. Guano also accumulates on the exterior of a home where bats enter Bats are the only home invader species that routinely leave its droppings peppered on a vertical wall. This is often a good signal that bats are entering a building at a certain point.

Bats Are Protected

Home owners must also keep in mind that the bats that are living in your attic are protected by federal law. It is unlawful to harm them; and killing the bats is unnecessary. A quality exclusion job solves the bat problem for the long term. Exclusion also eliminates other species from the attic that may be there as well.

Small "volcano" of guano accumulated under a roost site in an attic. Screening corroded by excrement with feces pellets trickling through.

The bottom line is that, you need to make sure that bat work is done in a way that is within the law and that leaves you with satisfactory results. Most people need professional help to accomplish this. If you think that you need professional help please feel free togive us a call. For additional information on removal of bats from your home please see our section below on How We Remove Bats from Attics.

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