How To Get Rid of Bats

Bats are actually great to have around, as they eat thousands of nasty bugs such as mosquitoes. However, if the bats are nesting some place where they don't belong, such as your attic, this is how you can get rid of them.

If Bats Are Inside a Building

1. Find out if you're dealing with a nursing colony. If you remove the adult bats before the pups can fly out, they'll die in the building. Not only is this inhumane, but it's also impractical because bat carcasses are hard to find and get rid of.
   • Note that bats in some regions can fit through a hole the size of a dime!
   • It takes about five weeks for newborn bats to fend for themselves.
   • In the US and Canada, the maternity season falls between May 1 through August 31.
     • The maternity season begins as early as mid-April in the southernmost U.S.
     • In Indiana, most bat pups are born in late June or early July, so you can begin or resume bat removal by mid-August.
     • In Washington state, you'll want to avoid bat removal in May, June, and July.
2. Don't get rid of bats during the winter when they're hibernating. There won't be enough food for them to survive outside. If the bat population is decimated, you'll probably notice more insects like mosquitoes and garden pests come spring.
3. Determine where the bats are getting in and out. Look for bat droppings (guano) on or below the entrance. Bat droppings have tiny bits of insect shells, so they're sparkly in the sunshine and crumbly in texture, unlike mice droppings which consist mostly of plant matter. They make an amazing fertilizer. 
   • Try to avoid inhaling the bat droppings. You can get histoplasmosis (flu-like symptoms). The very young, very old, and those with weakened immune systems are especially vulnerable.
   • If you can't identify the openings by the droppings, such as if the bats haven't been there for a long time, watch carefully to see where they emerge from at night.
   • These are some common points of entry:
     • broken or poorly-fitted screens
     • loose or missing shingles or tiles
     • places where flashing or boards have come loose
     • locations where pipes or wiring enter buildings
     • where walls meet the eaves at the gable ends of an attic
     • where porches attach to the main part of a house
     • where dormers meet the roof
     • cracks and crevices where siding forms corners, or at places where it meets windows, doors or chimneys
    
4. Prevent the bats from re-entering. There are two ways to go about doing this.
   • After they leave at night to feed, nail or staple a screen or fine hardware cloth over the opening. By the next night, only some of them will be gone, so you'll need to remove the covering so the stragglers can leave to feed (they'll be hungry). Bats typically feed on a 24-48 hour cycle, so you need to go through a couple of "sealings" to get rid of the entire colony. This can be pretty time-consuming if there are many openings throughout the building, as bats typcially won't use "alternate exits".
   • Ideally, you should use one-way devices. This is what professionals use. Once all the bats are gone, the devices are removed and the holes are permanently sealed. You can purchase one-way devices, or make your own from netting, PVC pipes, or empty caulk containers. Here's how to make them out of netting:
     • Cover the opening with plastic or lightweight, flexible netting with 1/6 inch (0.4 cm) mesh or smaller, but only secure it along the top and halfway down the sides. It should extend 18 to 24 inches (46 to 61 cm) below the bottom edge of the opening. Repeat for all openings.
     • Keep the netting in place for a minimum of five to seven days to ensure all bats have exited. Then permanently seal the openings with silicone caulking, caulk backing rod, hardware cloth, or heavy-duty netting.

If Bats Are Outside

1. Put a cup of moth balls in the middle of a small square of cheese cloth (about 5"x5"). Tie it to create a sack. Tie the sack to the area where the bats are nesting (while they're gone). The odor will discourage them from nesting there. You might have to do it more than once, however, since bats tend to return to old nesting sites.
   • Don't use moth balls inside a building. Bats living indoors are usually maternity colonies, and the mom bats are quite stubborn. Light, noise, and garlic won't work, either.
     • To be effective indoors, the active ingredient in mothballs, naphthalene, must be used in such large quantities that it poses a significant health hazard to humans.
2. Spray an aerosol dog or cat repellent on the spot where bats hang out, but do it during the day when the bats aren't around.
3. Hang Mylar balloon or strips of tin foil in the roosting areas and allow them to move in the breeze.

Tips

• Ultrasonic devices are ineffective against bats.
• Putting up a bat house won't draw bats away from your home or other undesirable spots. But, it'll give them a place to stay once you've sealed the building, so that they stick around your home and continue eating bugs.
• Don't try to catch the bats. It'll be difficult, and they might bite you. Plus, there's no guarantee you'll get all of them. Some of them might be hiding in the walls, or other crevices where you can't get to them.
• Scoop up any bats you find on the floor with a shovel or dustpan. Take it outside. If you didn't knock it down, it's probably sick. Bats are no more likely to carry rabies than any other woodland creature. You should be careful when handling any woodland creature.

Warnings

• Don't use pesticides. Some species of bats are endangered. In some areas, using pesticides to get rid of bats is illegal. There are other ways to get rid of them, and wherever they go, they'll eat bugs and garden pests, and they'll fertilize the soil with guano (their feces).
• Don't attempt any of these measures in the United Kingdom. In the UK all bats are strictly protected and it is a serious offence to disturb their roosting and breeding areas.