Big brown bat, a common species in South Carolina roosting
Source: USDA Forest Service – Southern Research Station , USDA Forest Service, SRS, Bugwood.org
Have you encountered a stray bat flying around in your house? Bats that fly into human living quarters are usually lost youngsters whose primary goal is a safe escape. They often will leave on their own if windows or doors to the outside are opened while others leading to the rest of the house are closed. Be patient and assist the bat by turning off lights and ceiling fans, and it will eventually find its way.
If you have determined that the bat has not had any contact with people or pets, and the bat cannot find its way out, isolate the bat to a smaller area and follow these steps to safely catch and release it:
- Wear Gloves & Long Sleeves: As with any wild animal, including bats, you should avoid handling them with bare hands.
- Do not chase. Wait until the bat lands on a wall and cover it with a large can, cardboard box, or container.
- Slip a piece of cardboard under the container.
- Slowly turn the container over with the piece of cardboard and release the bat outside. It is best that you do this whenever it is dark out so the bat can avoid predators.
- Place the container on an elevated surface and allow the bat to crawl out on its own. If it doesn’t leave, it might be injured or sick and need a wildlife rehabilitator.
Bats in Living Quarters
If a situation arises where you or a pet happens to wake up in a bedroom or living space where a bat is present, and you are uncertain of any pet-bat contact or human-bat contact has taken place, assume that exposure has taken place. Safely contain the bat and contact the South Carolina Department of Health and Environmental Control (SCDHEC) to determine if there has been any exposure to rabies and have the animal tested if necessary. Less than 1% of bat populations that occur naturally in the wild have rabies, so it is important to remain calm and not panic if this situation happens. Still, it is best to err on the side of caution when it comes to potential rabies exposure.
Help!… I Have a Whole Colony of Bats!!!
Exclusion is the only effective method of ridding your home of bats. With the exclusion method, you are installing one-way exits on all major exit/entry points for the bats. There is no magic potion or spray on the market to kill or repel bats, and there isn’t any pesticide labeled for use on bats.
If you notice bats in a structure, the first thing that you need to do is to identify where bats are entering and exiting. These observations should take place at dusk whenever the bats emerge in the evenings to feed. If bats are using a structure, there will be brown rubbings visible on the holes or gaps or behind shutters or gaps between buildings. There will also be bat droppings, called guano, underneath major entry/exit points. Once roost entrances have been located, the bats can be excluded by placing a device to prevent a bat from reentering the structure.
It is very important that you do not perform exclusions from May to mid-July. During this time, bats are raising their young (called pups), and the babies have not yet developed the ability to fly. If you attempt to exclude when the young have not learned the skill of flying, starved young become trapped within a structure, resulting in serious odor issues due to the young dying in crevices within the structure that are not easily accessible. It could also increase the likelihood of pups entering living spaces in homes due to them searching for their mothers. Therefore, early spring (March-April) and the fall (August-October) are the best times of the year to exclude bats.
After bats have left the building, begin exclusion by covering chimneys and vents with half-inch hardware cloth screens, installing draft guards beneath doors, and sealing any other possible access routes, especially around screen doors, windows and plumbing. Bats can enter very small spaces. Seal any gap or hole greater than ½” in diameter with caulk, steel wool, or any other durable material.
Bat exclusion devices can be purchased or made from a 2-inch-diameter PVC pipe, clear sheets of plastic, and empty, clean caulking tubes with the ends cut off. Netting also may be used. For specific directions on how to make or where to buy bat eviction devices, visit Bat Conservation International and GADNR Examples for Bat Exclusion Device Installation.
The devices should be left in place for about a week or two to ensure that all bats have left the roost. Once there are no more signs of bat activity, the exclusion device can be removed, and the holes and gaps can be filled with a more permanent solution. Bats cannot chew and make holes, so once the holes are filled properly, the bats will not reenter them. Exclusion is a great method because it takes place during the daytime, and it doesn’t involve the handling of bats.
It is important to note that once bats are excluded from a building, they will attempt to return to the same building the following spring. Therefore, supplying the bats with an alternative roost in the form of a bat box is beneficial to the bats and to the homeowner, as bats are voracious insect consumers. Be sure the bat box is of sufficient size to house the size of the colony displaced.
Other Methods
Harmless repellent devices would seem ideal, but none are known to be effective. Thus far, all ultrasonic sound generators tested by reliable bat experts have proven ineffective, and some may endanger people or even attract bats.
Naphthalene flakes (moth balls) are also not effective. To be somewhat effective for bats, they require large amounts of flakes requiring frequent replacement and are only effective in small or tight places. The amount needed can cause irritation to humans and pets and should not be used near humans or pets.
Aerosol dog and cat repellents may discourage bats from using a particular roosting spot for periods of up to several months. They have been used effectively to prevent bats from night-roosting above porches. The spray is applied by day when bats are not present. Aerosol repellents are not an adequate substitute for exclusion in the case of day roosts and should never be applied when bats are in a roost. In many cases, suspending 2″ wide by 7-10″ long strips of aluminum foil or helium-filled Mylar balloons at a roost will deter bats. In addition, using bright, artificial lighting in the attic during the evening can discourage bats from roosting.
Bats are Important: Unfortunately, many bat species are declining due to White-nose syndrome and are not seen in a positive light by the public due to the many myths that surround bats, like they attack people, fly into people’s hair, are blind, or will suck your blood. In fact, bats are fascinating creatures and play a critical role in our environment. In addition, they are the only mammal on Earth that is capable of true flight. There are 15 species of bats that are found in South Carolina. Bats are one of the top predators of night-flying insects (including mosquitos) and play a huge role in our economy. According to the South Carolina Department of Natural Resources, bats save South Carolina’s agricultural industry over $115 million each year due to their suppression of insect species that can be a pest to some of our crops and forests, which in return reduces the usage of pesticides.
How can you help bats:
- You can help bats by reducing the use of unnecessary lights and reducing light pollution. Turn off lights whenever they are not in use.
- Leave Snags – when they don’t create a hazard, leave dead or dying trees (snags). These dead trees can create potential roosting habitat for bats. Snags are also extremely beneficial to other wildlife species, like woodpeckers.
- Go Natural –promote plant diversity and add native pollinator plants to attract insects. Bats in South Carolina can eat thousands of insects in one night. Consider planting white or light-colored plants that tend to attract nighttime pollinators. Bats will also roost under the bark of trees that have loose bark, like white oaks (Quercus alba) or shagbark hickory (Carya ovata).
- Reduce insecticide usage.
- Do not disturb them! Avoid disturbing bats that roost under bridges, caves, etc.
- Bat houses can be a great addition to a property, but they can be hard to get a bat colony to move into. However, promoting natural bat habitat first is the best option.
Resources:
- https://www.dnr.sc.gov/wildlife/bats/index.html
- https://www.dnr.sc.gov/wildlife/bats/SCDNRBatIDGuide.pdf
- https://www.batcon.org/about-bats/bats-in-homes-buildings/
- https://scdhec.gov/health/diseases-conditions/insect-or-animal-borne-disease/rabies/preventing-rabies/bats
Originally published 01/2024
