Fixit: Tips for discouraging bats - and pigeons

Q I have a problem with bats near my front door. There is white gunk on the siding and the other night one was in our home. How can we rid this area of bats? I've thought about leaving the front light on all night, but that could be costly. Can you help?

A Are you sure it's bat droppings you see? In daytime, you probably can see them roosting in overhangs directly above the droppings. Or watch the area about a half-hour before dusk to see if they are coming out from wall or attic cavities. Bats will start leaving about dusk, with the last bat out within an hour of the first.

But first, let's consider another likely scenario: It could be pigeon droppings that you are seeing, and the bat indoors is just a coincidence.

Repelling pigeons can be difficult. Sometimes motion and noise will scare them away. Try mounting flags on rails, tying ribbons to posts or mounting wind chimes. The noise doesn't necessarily have to be grating or loud. This may be only a temporary fix, however, because the birds can become accustomed to the movement and noise.

Applying a sticky bird repellent tape (available at hardware stores) where they roost may help. Eliminating food sources is another way to discourage them, but that can be hard to do in some settings.

The real solution to a pigeon problem is modification of their potential roosting area or a reduction in the number of birds. Consistently destroying nests will help. (Because they aren't a protected species, you can destroy pigeon nests, but not the nests of songbirds and other protected species.)

Readers have suggested discouraging pigeon roosting by altering the roost. If the area on which the birds land is at least an inch wide, attach string lengthwise across the area at one-inch intervals. The birds don't like the loose, twisty string for a perch and will eventually give up.

Evicting bats

The best way to get bats to leave is to eliminate roost-friendly sites. To do that, bat experts recommend:

• Shining a bright light on the spot 24 hours a day for a week.

• Using nontoxic aerosol dog or cat repellents available at hardware and garden stores. Apply the spray during the daytime and only when bats are not present.

• Hanging Mylar balloons or strips of aluminum foil from the porch ceiling.

Don't use sticky bird repellents. Some of them are marketed as a deterrent for bats, but they are inhumane. Bats can become trapped and die.

If, in your twilight check of the house, you do see bats exiting your house, note all of the exit points and count the bats. (Do this twice to ensure that all holes are identified and bat numbers are accurate.) If there's only one exit point, plug it as soon as the last bat leaves (that's why you counted the bats). If several holes are found, plug all but one during daylight. Wait a day or two to give the bats a chance to get used to using the last opening, then plug it as soon as the last bat has left in the evening. Make a temporary seal of steel wool to keep them out. Permanent bat-proofing requires mesh hardware cloth, plywood or aerosol-foam insulation.

Although you may not want to think of them beyond getting rid of them, experts advise against discouraging them too much. They have their benefits; for example, they devour lots of insects during their nightly hunts. Consider putting up a bat house nearby for your displaced bats. That way, they'll stick around without creating a nuisance.

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av. S., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@startribune.com. Past columns are available at www.startribune.com/fixit. Sorry, Fixit cannot supply individual replies. Fixit appears daily in Source except on Friday.