Battling Bats in Your Home
Bat-Proofing Your Cave
In the Nick of Time
One of the easiest and quickest ways to find bat entrances is by watching for them at night (you might lose a little shut-eye, though). Since they're nocturnal, they'll leave their roosts just before dark and return just before dawn. Pick the time that's best for you, and go on bat watch for a few days. It should tell you what you need to know.
To keep bats out of your home, you first have to determine where they're coming in. Bats can squeeze into very small spaces — literally the size of your thumb — which is why it can be difficult to exclude them, but it isn't impossible if you can locate their entry spots.
The following areas are common bat-entry sites:
Chimneys, including the flashing around them
Flashing and fascia on other parts of structures
Roofing, including ridge caps and roof vents
Soffits and soffit vents
Electrical and plumbing conduits
One way to detect bat entrances is by their feces. If you find musty-smelling droppings on the ground or stuck to the outside of your house, there's a good chance bats left them there. Look up from the guano spot, and you'll probably spot the entrance to their roost. If it's been in use for even a little while, the edges of the opening should have turned dark brown from the oil and dirt that rubs off the bats' bodies as they enter and exit their roost.
Ruling the Roost
A Fine Mess
Never try to eliminate a bat colony during the summer. This is prime baby bat-rearing season, and you run the risk of trapping youngsters who can't fly yet.
Once you've figured out where bats are roosting, you can take steps to eliminate them. There are two optimum times for doing so: in the spring before migratory bats return to roost, and in the fall as they leave for the winter. Timing is important here; you don't want to trap baby bats inside your home, as they'll die. When they do, their carcasses will cause odor and insect problems.
Because bats don't chew through materials, you can use just about anything you have as barriers. However, anything you use must be anchored securely as bats will push aside shoddy workmanship.
No matter what you use, be sure to give the bats one escape route until you're sure they've all flown the belfry. Why? Not all bats leave the roost every night. If you were to seal off all entrances, you'll trap some of them inside. Not only is this the kiss of death, especially for baby bats, but trapped bats will typically seek alternative exits and come out inside of buildings.
However, you do want to make sure all bats that left can't get back inside. Building a one-way bat door will do it. Here's how:
Choose your material. Polypropylene netting, also called bird netting, is simple to use, widely available, and very effective. You can buy it at a hardware or home-improvement store. A heavy plastic garbage bag is another option. Just remember: You want a pretty decent length of either material, enough so it will drape down under its own weight but not so long that the bats can't come through.
If you're using a bag, cut both ends away. If you're using netting, tape or staple the edges together to make a tube.
Install the bat door by taping or stapling it in place around the entrance to the roost.
The material will open wide enough for bats to crawl out, but they won't be able to reverse direction and climb back through. Watch the door for several nights. After three to four days, you shouldn't see any more bats coming out. At this point, you can remove the door and seal the entrance.
If you want to hasten their departure, you can apply naphthalene-based chemical repellent to the roosting area. This substance makes it difficult for bats and other small animals to breathe, and will typically make them seek fresh air.
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Excerpted from The Complete Idiot's Guide to Common Household Disasters © 2005 by Paul Hayman and Sonia Weiss. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.
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