Build a Bat House for Natural Pest Control

North American bats polish off hordes of mosquitoes every night. Support their efforts by providing a bat house based on this advice from Bat Conservation International.

| September/October 1990

The word "pets" has been nudged into disrepute by animal-rights advocates who consider it patronizing and demeaning to the animals, giving them approximately the status of toys: cute, playful objects that exist solely for our amusement. But the term "companion animals" does more than elevate dogs, cats, hamsters and other domesticates kept around the house. It also suggests that every animal is a fellow traveler, whether bred to our specifications or not, whether we feed and pet it or not, even whether we like it or not. Which brings us to bats, those ace mammalian fliers long maligned and widely regarded with disgust, as though—creatures of twilight and night—they intend us evil.

Fortunately, the myths are starting to evaporate, thanks in great measure to scientists like Merlin Tuttle, of Bat Conservation International (BCI) in Austin, Texas. Bats do not get entangled in human hair, nor are they any more prone to rabies than most other mammals. True, there is a species in Latin America that takes a blood meal from cattle and is called the vampire bat. But, when you think of it, mosquitoes do that to us all the time. We retaliate by spraying the hell out of them, meanwhile suffering the toxic indignity of chemical residue leaching into the environment and eventually into our very own tissues.

The irony in today's lesson is that most North American bats are insectivorous, capable of polishing off hordes of mosquitoes every night. So it makes terrific sense to let them do their thing, even to encourage it, not only by supporting efforts to preserve existing bat roosting sites in your community but by creating new ones—in your own backyard.

You can order a ready-made bat house from BCI and mount it on the side of a house, barn or tree, in which case a portion of the money you spend will go into BCI's conservation work, which is money well-spent. Or you can build a bat house yourself in an afternoon by referring to the bat house diagrams that accompany the bat questions and answers provided by BCI. Either way, if the boxes you mount end up being occupied, the local mosquito population will find itself nicely dented next spring. And you will find yourself feeling a little more hospitable and companionable!

Where to Install Your Bat House

Bat houses located near a permanent source of water, especially a marsh, lake or river, are by far the most likely to attract bats. They should be hung roughly 12–15 feet above the ground, where the approach is unobstructed by vegetation or utility wires and they are sheltered as much as possible from the wind. A bat house can be placed on a tree or pole, although those attached to the side of a building have had the most success because they provide temperature stability.

Temperatures Bats Tolerate

Since appropriate temperature may determine how (or even if) your bat house is used, you may wish to consider several factors before mounting it. Lower temperatures, due to higher altitude or latitude, require that bat houses intended for use by nursery colonies be oriented to receive maximum sun, especially in the morning (southeast exposure). Another way to gain heat absorption is to add tar paper or dark-colored shingles to the bat house roof. Even in hot climates, bat houses should be positioned to receive morning sun.

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