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Bats in Buildings

Bats in Buildings

Bats have long been misunderstood, feared and unfairly persecuted by people, and their appearance around the home can cause a lot of panic. Bats actually have a very low likelihood of carrying disease, are quite timid of people, and are among the most beneficial animals to have around for backyard & agricultural bug control. Still, there is some risk associated with bats in buildings, particularly when they turn up in the human living space.  Here are a few common scenarios and how to handle them:

  • If you’re concerned about a colony of bats roosting in your attic, eaves, or other part of your home and you wish to “evict” them, a process called bat exclusion must be done following proper methods and seasonal “safe dates” so that bats are not harmed in the process. Please see the Excluding Bats section below for more info.
  • If a bat is flying around in your living area and there’s no chance someone was bitten, the easiest way to get it back outdoors is to shut yourself in the same room as the bat, leave a light on so you can see, and open a window or door to the outside. Crouch down at the other side of the room, and stay still and quiet so the bat can calm down, too. Watch until the bat flies out – this way you can be sure it has left. It should only take a few minutes for the bat to detect the exit using echolocation. The bat will not land on you or “attack” you. It’ll swoop lowest at the center of the room due to flight dynamics.
  • If a bat inside your living area gets tired and lands in a reachable place, you can put leather work gloves on, cover the bat with a small container (like a quart-size yogurt tub) and carefully slide a lid or piece of cardboard over the opening to enclose the bat inside the container. If it’s nighttime, go outside and hold the container up high in front of you (facing away from you), then remove the lid and tip the container slightly downward so the bat can crawl to the edge and swoop out. Or put the container someplace elevated, on its side & uncovered so the bat can easily crawl out and take flight. If it’s daytime, walk the container to a nearby tree or forested area and release the bat at the base of a tree or in shrub cover so the bat has a place to climb and seek shelter until dusk. Bats have a hard time taking off from the ground. Not that brave? Your local Animal Control Officer or a professional wildlife control company should be able to help (as long as you know exactly where the bat is).
  • Sometimes bats get into the living space at random, like when a sliding door or garage is left open in the evening (bats may follow moths inside). Or they might take shelter in an un-capped chimney and pop out into the home by accident. But finding a bat in your living space could also be a sign that a colony roosts in your attic…so it’s worth a look. Please see the Excluding Bats section below.
  • If a bat appears injured or needs care, and there’s no chance someone was bitten, please contact a NJ Licensed Wildlife Rehabilitator near you. The list tells you which ones treat bats.
  • If direct contact between a bat and a person or pet may have occurred, NJ residents should call their local health department to discuss the case. Most likely, the Health Department will recommend submitting the bat for Rabies testing as a precaution. Additional information and instructions are posted on the NJ Department of Health’s Rabies webpage. Your local Animal Control Officer may be able to assist.

Excluding Bats from an Attic or Building

Big Brown Bats roosting on rafters in an attic. Bats are not rodents and they do not “nest.”

Most bat species in our region naturally roost in trees, though some will gladly take up residence in attics, barns or other human-made structures. For maternity colonies especially, a house attic is warmer, safer from predators, more weather-proof and longer lasting than a tree. In developed areas, buildings are simply more available than the mature trees and snags with cavities or flaky bark that bats prefer.

If you’re concerned about a colony of bats roosting in your attic, eaves, or other part of your home and you wish to “evict” them, a process called bat exclusion must be done following proper methods, at the right times of year (“safe dates”), so that bats are not harmed in the process.

New Jersey’s “safe dates” for bat exclusion are April 1-30 and August 1-October 15.

Please refer to New Jersey’s Nuisance Wildlife Control Guidelines for Bats (pdf, 95kb) for details. These guidelines avoid sensitive times of year when flightless pups (in summer) or hibernating bats (in winter) may be present.

If you’re unsure where to begin, a Nuisance Wildlife Control specialist can be called out for an inspection. They can confirm if bats or bat droppings are present, identify entry points into the building, and perform a bat exclusion at the appropriate time of year. There are many professional bat exclusion companies that service NJ.

Note: Physically removing bats or poisoning bats is NOT legal and NOT effective. Fly traps or glue traps should NOT be used in places where bats may encounter them. Like all of NJ’s native nongame wildlife, bats are protected by law under the NJ Endangered and Nongame Species Conservation Act of 1973, making it illegal to harm, harass, capture, or kill bats, or to attempt to do so (with the exception of Rabies testing as described above).

You can help pinpoint the bats’ access points: On a warm, rain-free spring or summer evening (at least 50°F), stand outside your home at sunset and watch closely at dusk for bats to fly out. Common access points are attic vents, the peaks where your house siding meets the trim or roof line, dormer window areas, gaps behind a chimney, and the eaves. As long as the weather is suitable, adult bats always leave their roost at dusk to hunt insects and drink from nearby waterways. Bats may come and go throughout the night and will return to the roost by dawn.

Bat Houses for Evicted Bats

Bat houses – also called bat boxes – are a great way to provide displaced bats with a new roost while keeping them in the neighborhood for bug control. Bat houses also reduce the chance of your “ousted” colony searching for another way into your home or settling into someone else’s. Bat houses should be mounted at least 12-15 feet high, ideally on the sunny side of a building where people and pet activity is light. Keep in mind that bat droppings will land below…so avoid mounting bat houses over doorways, windows, your patio grill, etc. Mounting a bat house on a pole or post in a sunny part of the backyard is also an option, but bat houses on buildings are far more likely to be used.

Both the Conserve Wildlife Foundation and Rutgers University offer FREE bat houses for evicted bat colonies.  Each bat house can hold around 80 bats – they’re happy to share space and warmth!

Want to build your own bat house? There are lots of different designs out there. Here’s one that we like:  Bat House Floor Plans (pdf, 255kb)

More Information


MacKenzie Hall
NJDEP Fish and Wildlife
Endangered and Nongame Species Program | 908-236-0184

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Department of Environmental Protection
P. O. Box 420
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Last Update: October 12th, 2022