We have a bat problem. How do we move them on in a friendly way?
—Maria Cordeiro, via e-mail
Clearing out bats is a multi-stage process that takes time, patience, and probably a few late nights. First of all, friends don’t evict friends without suggesting alternative sleeping arrangements. For bats, this means bat boxes. (They’re about the size of birdhouses, but insulated, with rough interior walls that the bats can cling to.) Before situating your bat boxes, determine where the critters are getting into the cottage. Time for some nighttime surveillance: At dusk, wait outside your cottage and watch where the bats enter and exit; place the boxes near these spots. Seal up all these entrances and exits (bats can squeeze through a space as small as six mm) except one. After a few days, the bats will learn that this single hole is now their only option to get in and out. Then, one night, after the bats all leave, cover this last opening with a piece of hardware cloth. Leave it loose at the bottom to make a one-way exit door. Bats inside can push it out and leave, but can’t get back in. You can seal up this hole for good after a few weeks.
Timing is everything here: Don’t boot out the bats in June or July, baby season, since the young left inside may die. August or September (or early spring) are better options.
