Twice now, I have spotted a bat in our home. My husband and I recently purchased this house. As careful, first-time buyers we made sure to dot all of our i’s and cross all our t’s. We hired a reputable building inspector and he spent hours checking into all possible or potential problems with our to-be home. The house was built in 65′ and as expected, the inspection brought up a few concerns. What did come up seemed minor and do-able: until the bats flew in.

Now, I don’t know for sure if we have a bat colony roosting in the house. But watching my husband flailing around the house, swatting at these moth-like flying mammals, all the while experiencing my first lock-myself-in-the-bathroom screaming session, was enough to kick-start a thorough investigation. I called the bat police. If we have bats in the house, their removal will be a potentially costly service. Likewise, there are specific health concerns that set off significant alarm bells. So, let’s talk bats, in hopes that as you look into the purchase of your next home, you make sure to check for the tell-tale signs.

First Things First

Just to get you thinking seriously about this concern, consider the fact that bats are not pests. In most states, as in most places in the world, these unique critters are both endangered and protected. Indeed, when I first googled my problem, I was expecting a sea full of comforting headlines: BAT EXTERMINATORS AT YOUR SERVICE. GET YOUR EFFECTIVE BAT POISON HERE.  However, this was not the case.

Most of my research sang to the tune of bats being the least understood and most persecuted animals in the world. I was ignorant to the fact that people, our environment and our legislation, love bats. Okay, I get it now. Without bats we could be swarming in a swamp full of blood hungry mosquitoes. Bats are serious insectivores and their populations are on the decline. For this reason alone, they need our protection. But beware, homeowners who unwittingly house them, may end up paying for this unconditional love. It is best to avoid this problem completely, by not buying into a house with bats.

If you are interested in purchasing a home that is on the old to older side, it won’t hurt to look for signs of bats. Chat with your building inspector before an official house inspection and see that he/she is savvy to these indicators. The following signs may be evidence of bats roosting in your to-be home:


Look for unusual brown or grey stains in areas where bats might potentially enter the home. These entry points may be attic vents, cracks and holes under rotted eaves, where a chimney meets the house and openings where the pipes and wiring enter the house. The main characteristic of these stains is that they are oil based and difficult to remove.


Guano is a pretty, Spanish name for bat poo. The droppings will be found around the roost site. Guano droppings are pellet-like and give off a particular scent. This ammonia or musky smell may be present near the roosting bats, notably in the summer. In the winter months, the scent lessens as the bats have either migrated or are hibernating. However, Guano presents the most dangerous concern in housing bats. Inhaling dust that contains fungal spores found in guano can cause a serious lung infection. Histoplasmosis is the name of this fungal lung disease associated with bat droppings.


If your inspector thinks they hear the sweet chirping of baby birds, have them double check that this cute social chatter is not emerging from a bat colony. Bats audible chatter is very similar to that of birds.


The reason for all the ominous fore-warnings, is not that bats flat-out creep me out. Yes, I was terrified when I first saw one flying about our house. Now, after having done some research, I have gained a vast respect and curiosity for these amazing mammals of the night. Still, who wants to live with bats? The reason to consider checking for signs of roosting bats, is that they can be very tricky to remove. You can’t poison them. It is illegal and otherwise ineffective.

Proper bat removal usually involves an intervention by a bat removal company. The company will use exclusion methods to remove the bats. After that, they will seal up any potential re-entry points in your home. Depending on the size of the bat colony and how long they have roosted, the damages, guano clean-up, re-insulation and repair can be costly and time consuming. So buyers beware of bats. Yes, they are vital ecosystem managers and need to be protected. In conclusion, let them be protected by our laws and not by our roofs.


– Only mammals in the world capable of natural flight.

– Can consume 500-1000 insects per hour.

– Protected in the United States and should never be harmed or killed.

– Make up nearly one quarter of all known mammal species.

– Use echolocation, a kind of natural sonar, to navigate and locate food.

– Gentle, passive creatures that will only bite in self defense if they are picked up and handled.

– Never touch a bat with your bare hands! Although rare, sick bats may carry rabies.

– Can crawl through openings as small as 1cm in diameter.

– Over the past 20 years nearly 80 percent of the country’s bat population has been lost.

– To help conserve the bat population, build a bat house. It may attract bats to roost near, but not in your home!