She's got Bats in the belfry, Squirrels in the attic, Owls in the loft.

Do you hear noise in the attic? It smells like cats upstairs? What about that grey cloud of birds that I see at dusk every day? Oh dear, oh dear! Well… bats are not necessarily bad, they eat bugs! However they can make a giant mess and can cause major damage to a home. Not only can they damage your home but in many cases they can cause damage to your body. While there are plenty of good reasons to attract bats to your property, there are definitely reasons to evict them from the home you unintentionally share. Bat droppings can accumulate very quickly and cause a strong, rancid, ammonia smell. Excretions can wick through the ceiling drywall and cause unsightly and unsanitary spots on your ceiling. They can even rot the sheetrock of your ceiling and in extreme cases cause collapse. Bats also cause Histoplasmosis, which can resemble tuberculosis but is unresponsive to treatment. This is caused by the fungus that grows in the dried guano, which turns into a yeast when it is incubated at body temperature. So… Bats in the Belfry, while good for mosquito and insect control, is not necessarily a good thing.

Types of bats

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The bat order is divided into two suborders on anatomical grounds: Megachiroptera or fruit bats and Microchiroptera or insect eating bats. Fruit bats include the largest of the bats, flying foxes, which can weigh up to three pounds. Their diet is almost exclusive to fruit, nectar, and pollens. Insect eating bats include the smallest of the bats. Despite the name, these bats can also live on fruit. Many eat insects and sometimes they can even eat larger animals. There are several species that even catch fish as they skim the water. Of course there is also the South American vampire bat, which feeds entirely on blood.

In the Northern Hemisphere, the most common bats are the Old World horseshoe bats, getting their name from the horseshoe shaped appendages they sport on their faces, the little brown bats Myotis, Eptesicus and Pipistrellus all have regular noses and belong to the plain-nosed bat family of “Vespertilionidae”

There are over a dozen species of Myotis in the United States. They are found from Alaska to Florida. The small brown bat M. Lucifugus a colonial bat is found in all sorts of habitats including homes. It is only about 2 ½ inches long and has no tail. The large brown bat Eptesicus fuscus is found in the same geographical areas and is almost 3 times as heavy with a 12 inch wingspan. They are both susceptible to a fungus that devastates bat colonies by causing White Nose Syndrome, a disease that causes emaciation during hibernation which leads to death for many in the colony.

Freetail bats, of the family “Molossidae” are a group of communal bats that are characterized by a very long tail. Among this group of bats are the guano bats Tadarida. These bats live in enormous groups and produce guano in great amounts which is valued commercially for its fertilizing properties. Of these, the Mexican Freetail bat is probably the most well known, its most famous colony lives in the Carlsbad Caverns in the Southwest United States. This colony is enormous, numbering somewhere between 250,000 and 500,000 individuals. When they leave the cave, the column takes as long as twenty minutes to exit.

Who you gonna call?

The easiest and most effective ways to fix the infestation of a bat colony is to call a professional! While ropes of garlic may or may not have worked in the 1400’s I’m fairly certain they have gained immunity to this precautionary measure. Poisons are off limits – No chemicals or "sonic gadgets", either. Any company which tells you differently is probably just out to make a buck. Remember that bats are just as much mammals as your dog, cat or you and I and those chemicals powerful enough to kill or repel bats also kill and should repel humans. Bats though scary for some, are a federally protected group of critters. In a nutshell, there is really only one way to help rid your home of bats. Bat proofing!!

Bats are usually forced to roost in buildings when their other roosts, such as caves and suitable trees are obliterated. Some caves are ruined by flooding, dam construction, groundwater pollutants and burning of debris. Others are destroyed by mining, quarrying, tourism and vandalism. Development of land leads to the clearing of possible habitats in trees and so, the bats end up looking for a suitable home in the suburbs with you and me. Attics, garages, and any other cave-like structures are great camping and roosting spots! The general requirements for buildings to be used as bats roosts are known.

Bats will live behind shutters, under siding and roofing, gutters, soffits, under the flashing around chimneys which is loose, open garages, patios, porches and breezeways. Shutters are great spots to find males in transit. In really hot weather, the females may forgo the attic for a nice shady spot behind the shutters as well. Unusual roosting areas include sewers, wells, and…wait for it…graveyard crypts. Generally speaking, this is short term and is rarely noticed. Colonial bats that live in structures usually occur, near water and perimeters of woods where insects are abundant. In other words, they like the neighborhood and the comforts probably as much as you do.

Myth Versus Reality

The Myth: In our popular culture you have probably seen a movie or a clip of someone flailing about trying to beat bats away from their head or a bat getting tangled in someone’s luxurious locks like a giant wad of flying chewing gum. We, as humans have some kind of instinctive fear of these kinds of these situations. If you just look online for information about these critters you will probably find all sorts of stories that make these, horrible, furry, rabid, sky-rats seem like Kamikaze in their normal day to day (or night to night as the case may be) behavior. While doing research for this post I have found all sorts of odd things that have almost no basis in reality. Add to this, the fact that we use bats as a mascot for Halloween and Vampires, and they tend to kind of freak people out with their ugly little faces and sharp little razor teeth… but we are grossly misinformed by these rather nonsensical (albeit) scary, images and alleged situations.


The Reality: Unless you really need to shave your hair to get rid of the nest of flying insects that is attracting these hungry bats toward your head, there is nothing a bat wants or needs from your head. In principle, I don’t even think you can fool a bat into landing on your head, never mind getting tangled in hair. I am sure that at some point in the history of the coexistence of bats and humans there have been a few instances of a bat ending up in someone’s hair, but it’s probably because it was hurt, confused or some kind of really, really, freaky accident. A bat’s echolocation ability paired with its superb maneuverability can easily let it detect and dodge even one hair! Think about it, a bat can pluck a single gnat out of the air with ease, so its targeting system is actually rather awesome.

So why, then, are there bats all up in my face?

Bats are probably swooping by because we are giant, delicious bug magnets. We attract mosquitoes by the swarm, flies, gnats and other bugs that like to suck our blood or eat us. Batman, kind of has the right idea there, swoop down in the dark and save the innocent person from danger. Bats, unlike batman are just really hungry. So the occasional fly-by probably has something to do with the super tasty free buffet that we attract to us with our body heat and perfumes and such.

NA NA NA NA NA NA NA NA Bat-Proof! 

In any situation where you need to remove a bat colony the best option is proofing the structure against re-infestation. In most languages the word used for “bat” is the same as “mouse”. The way in which an infestation is handled is similar as well. First, we need to locate points of entry to the structure in question. This includes; broken screens, loose and missing shingles, gaps in flashing or siding, the abutment of joints at the ends of eaves, small holes where wires and such enter the building. Some exotic and tropical bats can even get into openings the size of a dime!

Nursing bats

Because we don’t want to trap any young in the structure, we have to make sure that the bats are not nursing. If it is a nursing colony, removal of the adults will lead to the death of the youngest in the colony. It is very difficult to find bat carcasses in any case. Doubly so for small ones, besides… it is not very nice and its against the law. The maternity season for bats can begin as early as April and as late as June so, you need to wait till the nursing is finished, typically five weeks for nursing pups to fend for themselves. If you have missed the deadline to start evacuation (set by the fish and wildlife service) you can sit back and plan for a month or so of what you can do with your reclaimed space once the evacuation is finished.

When the nursing season is over and we have determined that the time is right for the removal of the colony, we can start to seal all of the entry and exit points from the structure we wish to evacuate. We need to make sure to leave a one way door and for a bat this usually takes the shape of a cone or netting. They can fly to the opening and squeeze through but, Ha! It is indeed a one way door! This is especially tricky if there are many openings to seal as bats will generally only use one entrance or exit. You may have to wait until dusk and watch the colony to see where it enters and exits. But once you have placed the cone/door you are in good shape. Bats usually feed once in every one or two days so it may take a couple of days to get them all out of the space. Generally though, after a week of waiting it will be safe to finish proofing the house… This means sealing the hole or holes that we have left open for the evacuation.

I really miss those mosquito eaters that used to live in my attic…

One good way to encourage bats to stay (around but out of your house) is to build them a house of their own! Just before an evacuation, if you would like to keep them around but not in your home, bat boxes are economical and encourage the eating of pesky insects. A Single bat can eat up to 2000 mosquitoes per day. Talk about an appetite! They also help pollinate plants and flowers. For some instructional plans and a nifty video for building a bat house you can just follow this link.


After years of collaborative research, the Organization for Bat Conservation has documented the key requirements for successful bat houses. Some of the main considerations to success include 3/4-inch roosting spaces, a nice sized landing area with a good surface to grip, and tall (at least 16 inches) and wide (at least 12 inches) roosting compartments. Research also shows that as the number of chambers increase, the occupancy rate rises. Houses placed on poles and structures tend to become occupied quicker than houses placed on trees. Bat houses should face south or east to take advantage of the morning sun. When painting the bat house, use non-toxic (water-based), latex paint to paint and only paint the outside. Your bat house should be mounted at least 15 feet above the ground.

Bats return from migration and awaken from hibernation as early as March in most of the U.S., but stay active year-round in the extreme southern U.S. Bats will be abundant throughout the summer and into late fall. Most houses used by bats are occupied in the first 1 to 6 months (during the first summer the bat house was erected). If bats do not roost in your house by the end of the second summer, move the house to another location.

Now for some random and useless bat stats and Jeopardy questions!

Bats are the only mammals to have true wings and flight
“Chiroptera” the scientific name for bats is derived from the Greek and literally means “hand-wing”
The smallest bats only weigh in around 3 grams
The largest bats only weigh in at around ½ lb.
Some bats can live into their thirties
Bats represent about 20% of the known mammal population
Some bats are monogamous and live together in family units, Moms, Dads and kids
Pteropus bats (also known as flying foxes or fruit bats) are the largest in the world
Bats live in every geographical region on the globe except for Polar Regions (and some isolated islands)
White-Nose Syndrome is a fatal disease for this flying mammal
Megachiropterans (big bats) are found only in the Old World tropics
Bats are associated with parasites, both internal and external, there is even one species of fly that no longer has wings because it lives only in the fur of bats
Frugivorious (fruit eating) bats are important seed dispersers
Desmoteplase an anticoagulant in vampire bat saliva is being studied for use in stroke patients for blood clots

Masters Services can help you with bats in your home or attic. Traditionally this is a service that has only been needed in the Houston (713) 723-4854 and Denver (303) 720-7096 service areas. Although, if you are in any of our service areas and are having trouble with bats in your home feel free to contact us for help.