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Pest of the Month: Bats

Pest of the Month: Bats

Wild animals are part of what makes nature so magical, and watching them can be highly enjoyable. While it’s important to coexist with animals in relative peace, they can cause countless problems when they take up residence in our homes or gardens. In this series, our Wildlife Management Specialist, Shawn Weeks, will educate us about some common household pests, and share some strategies for keeping them under control without dangerous chemicals or poisons.

This month, bats.

Habitat and History:
Bats are warm blooded, furry mammals. They are the only mammals capable of actual flight. Bats are nocturnal animals and feed at night, most from the wing, while in air. All bats are migratory creatures, usually colonizing in caves during the cold weather months and spreading out for several hundred miles during the spring and summer. Even the most solitary species colonize together in winter.

The bones in a bat’s wings are similar to the ones found in human hands and arms. Their fingers are extended and connected by an elastic skin that grows from the side of the bat’s body. The thumbs are free from the membrane and have claws for grasping.

Bats have excellent eyesight and use actual vision for long flight. They also use echolocation for locating prey and specific locations and targets. Echolocation is basically a sonar system that allows animals to navigate by the echo from various sounds they emit. Bats give off ultra sonic sounds slowly as they forage, then quicker as they pursue and capture their prey.

There are over forty different species of bats found throughout the United States and Canada.

All common North American bats feed on insects. Different species of bats eat different insects, but as a group they are all considered beneficial because most all of the insects eaten by bats are considered nuisances. For instance, a single little brown bat can eat 1,200 mosquitoes in one hour!

Most species of bats give birth to a single offspring in early to late May, depending on how far north they range. The young are unable to fly until around mid July. Newborns cling to their mothers while in flight until they become too heavy and are left behind in the roost while the female feeds. Nursery colonies only contain the females and their young. Males roost in other locations during this period.

Problems, Solutions and Health Concerns:
A single bat that enters a dwelling can usually be removed easily. Closing all doors to a room, and leaving a window open will generally prompt a bat to leave. You can also successfully remove a bat from a room with a large can or jar. Slowly move toward the bat, so as not to startle it, and gently put it over the bat. Slide a thick paper or piece of cardboard underneath and bring it outside to release it.

Remember to always wear leather gloves when dealing with a bat. They do have teeth, and can bite. They may be provoked to bite if they are being handled. If you are bitten while handling a bat, wash the wound with soap and water and get immediate medical treatment. Be sure to save the animal for examination. Bats are mammals, and are susceptible to rabies, as are humans, dogs, cats, etc. Fortunately, while bats are considered by many to be carriers of rabies, the actual incidence of rabies in bats is less than 1%.

If you are experiencing a large infestation of bats in your home attic or roof, there are ways of eliminating the problem without having to harm them. Note that bats do not cause structural damage, although they can leave behind guano (bat droppings), and stains on the sides of your house where they enter and exit. Depending on how large your colony is, they can also be noisy, especially when giving birth.

The best way to rid your home of bats is to seal up the structure at all points of entry. It is of the utmost importance that you do not completely seal up the bats’ entry/exit points while they are still inside your home or attic. Start out at the entry points by creating a “One Way” valve or gate. You can use a two-foot length of 4” PVC, attached by duct tape, to a soft wire mesh. Staple the mesh end to the house at the bats’ entry. This will allow the bats to exit safely, but not be able to return. The bats will not be able to grip the PVC and climb into the structure on return.

If you have a nursery colony of several mothers and pups, it is important to wait until the pups are self-sufficient, otherwise their mothers will not be able to feed them, and you will have several dead bat pups rotting inside your home. You definitely do not want that! Most bats can live on their own by the age of six weeks, so late August or early September is the best time for exclusion.

After installing the one-way valves, you can proceed to apply a sealant to all of the facial boards where they meet the siding, openings in the soffits, louvers and any other openings. You can use caulking, expansion foam, petroleum soaked rope, or fine mesh screening. Keep the one-way valves on for at least four nights, allowing the bats to leave safely, on their own. Then remove the valves and apply your sealant to those areas.

If you want to continue to welcome bats onto your property — just not inside your home — you can build or buy one or more bat houses as an alternative. Bat boxes can be secured right to the side of your home, or to trees or posts, and a small box can accommodate dozens of bats. Remember, the definition of “pest” is in the eye of the beholder. An animal that you don’t want in your home can be desirable outside of it. Bats, with their mosquito munching tendencies, are the perfect example. And bat guano is great for your garden and lawn!

There are many techniques and materials that can be used to rid your house of bats. Shawn has been performing bat exclusion work for over twenty years. If you have further technical questions, he can be contacted at info@weeksoutdoors.com

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  • JONY says:


  • Cele says:

    I found a large bat in my dressing room bedroom tonight
    It flewn into my ceiling to floor library section of my bedroom.ihave closed all hall doors in my upstairs where my room is located as well as my bedroom door, I am sleeping with my lights on in my bedroom. What is the best way to entice the bat out so I could throw a towel over him and remove him without a service exterminating the entire house. He frightens me

  • Barbara H. Evans says:

    I have tried for years to attract bats to my property. I have a bat house. What else can I do?

  • melissa says:

    i live in a suburban area that is forested…i have a ravine on either side of my property which is part of a ridge….i have a lot of mosquitos….i do spray my property and some of the woods with repellant which i disperse with my garden hose….this is because my daughter and her neighbor friend spend the majority of time outside….because of the trees i have many leaves in the fall, too many to haul away or burn in the burbs….so we blow them over the ridge into the ravine area….my daughter and i examined the mosquitos and found that they were tiger mosquitos which breed in wet leaves…despite my use of repellant specifically for mosquitos, i used to have a couple bats living in the little vent window on the side of my house that accesses the attic…you know the type, it has little wooden slats hanging downward at an angle just like a bat house ….they could not get into the attic because there is a piece of chicken wire/mesh nailed to the inside of the little window frame….their droppings fall on the sill and never make it into the attic…the wind eventually blows it away….we used to go into the attic in the daytime and watch the bats hanging there and examining the uniqueness of their creation….but now they are gone….this is my fault….i developed a problem with carpenter ants as it turned out but was afraid they may have been termites….so i called pest control….they exterminated the entire house….it killed just about everything after two sprays in cluding unfortunately my bats….i was so upset….no more of that….now i just want my bats back….it was such a joy to be outside in t he evenings with a contained fire watching overhead as the bats flew back and forth devouring the mosquitos….even using the mosquito spray only got rid of the mosquitos so far up above the yard….the bats flew above that area munching away…we always watched for them….i need bats back in my area….what is the best way to attract them….funny story from a friend at church, farm boy….he said when he was a teen he and his brother would go out at dusk and one night they were trying to shoot bats with their bb guns….their dad came out and asked them to stop for they would never hit the bats anyway…after just one more shot one of the bats dropped to the ground, then another….the father couldnt believe his eyes….he went to examine the creature….there was not blood these bats werent dead….the bats’ bellies were so full of bbs which they had caught in midair that it weighted them down to the ground….please allow that to be a lesson to you of the bat’s great ability and more….thank you for reading my post

  • BushraSiddiq says:

    I hope that you don’t mind my posting here.
    I am doing some research on bats and infestation of people’s homes and am looking to speak with people about their own experiences of bats living in their homes.
    It would be great to hear from any of you.
    Many thanks

  • Outdoorsman says:

    Hi Dana. I have come across a lot of confused folks over the years with my business. Most people are amazed that they find bats in their basements.
    The most common reason for this is they fly into an open chimney and find their way to the bottom. Once there, they can get into the basement from the clean out door on the chimney base. A lot of people don’t realize there is a door there, and more often than not, the door is in poor shape{ rotted and rusted, warped, broken off}. Chimneys should always be capped. I have been pulling bats, birds, squirrels, baby raccoons, etc. from un-capped chimneys for years. One winter, about 15 years ago, I removed a pure white Owl from a fireplace in the middle of winter. Animals are resourceful and opportunistic, arent they?

  • Dana says:

    We moved into this house two years ago and, in the first year, we got a little brown bat in the house three times. The first couple times it was in the basement. The third time it was flying around on the first floor. They are small enough that if you are very gentle but quick and you don’t have leather gloves, you can instead grab a large towl, fold it a few times and throw it over the bat and scoop it up gently. It’ll struggle and make buzzy-clicky noises at you–just don’t panic and squeeze it, but get it outside as quickly as possible. If they’re healthy they’ll just fly away when you open the towel, even in broad daylight. One of ours didn’t seem to be doing so hot–it was lying on the basement floor when we found it, and it kind of malingered around on the front patio when we let it out. The other two were fine though, and flew away.

  • Mollie says:

    We have had bats in our attic for the past couple of years. I haven’t really worried about it. Now have a 2 year old I have gotten a bit more cautious. We had a bat crawl outta the toy box one evening and I freaked. Lately the bats have been swooping around inside at night and getting a little too close for comfort. We have been catching them in a large fishing net and setting them free. (Which really makes no sense because they come home when they are done.) So I went and bought some of those no poison, sound emitting plug in things and haven’t noticed any indoors in the last 4 nights. I still hear them chattering in the roof, which I actually find peaceful (as long as they are not dive bombing my head.) It doesn’t say that they will work for bats on the packaging, but I thought, what the hay, lets give her a try. So far, so good.

  • Rachelle says:

    Thank you for this article. I love the bats and next to the dog they are
    man’s best friend.

  • Glenn says:

    The bats do an excellent job of controlling the misquito population. With no bats, we have the conditions we have now, where in some areas we cannot even go outside, because of the misquitos and the sicknesses they carry. I agree that you cannot have the bats in attics and such, but they are a neccessary part of the environment.

  • Marlene H. Rosenberg says:

    Seems to me that bats are less a “pest” animal than a beneficial one…considering its diet helps to clean up insects without resorting to chemical warfare. Bats have been dying off from “white nose disease” and their numbers are getting lower…..we should be making efforts to provide an inviting environment for them.

    • Jaime McLeod says:

      Shawn mentions repeatedly in this article that bats are beneficial. However, they can pose property and health risks when a colony of them moves into your home. Believe me, I know from the personal experience of having thousands of bats form a nursery colony in the crawl space above an old apartment I once had. It was not good for my family, or for the bats. The method that Shawn offers here for excluding them from a home is perfectly safe and, provided it is done when all of the bat pups are self-sufficient, does not injure the bats in any way. At the time of year when bat exclusions are performed, the bats are getting ready to give up their nurseries, anyway. If you want to encourage bats to take up residence on your property, bat boxes are the way to do this (again, as mentioned in the piece). All of these “pest” articles are about trying to live as harmoniously as possible with the animals around us. That’s not possible, however, when thousands of them are fouling your home with guano, or keeping you up at night with their screeching.

  • Ginger says:

    Our neighbor used a system like the one described in this article. It was successful in removing a very large coloney of bats. He took the bats to a cherry and apple orchard in Traverse City, MI. They welcome the bats. Evidently bats eats some kind of insect that damages the fruit crop. They will return to invade a neighbor’s house if released within a 50 mi.? radius of your house.

    • Jaime McLeod says:

      Just to clarify, the method Shawn is describing here doesn’t involve actually capturing any bats. It just creates a one-way door so the bats can leave your home, but not get back in.

  • C says:

    Trying to locate a bat house in Boston to purchase. Any suggestions?

  • candy mercer says:

    I’ll take all the bats anyone wants to “get rid of”….they are the “graveyard” shift , work while I sleep, and do a great job. I really appreciate them.

  • T. Sajda says:

    I didn’t realize that one could get rid of bats so easily. Very interesting article. Keep them coming.

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