Install a Bat House for Natural Pest Control
(Page 2 of 4)
September/October 1990
By the MOTHER EARTH NEWS Editorial Staff
What temperatures do bats tolerate?
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Since appropriate temperature may determine how (or even it) 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.
Nursery colonies of females and young normally prefer stable temperatures from 80-100° Fahrenheit, though some species tolerate temperatures higher than 120. Bachelor colonies frequently select cooler roosts, so even if your bat house is too cool for a nursery colony, you may still attract bachelors.
When can I expect bat arrivals?
Although there has been one report of bats moving into a house within hours, a year to a year and a half is a more common waiting period. Some highly successful bat houses were not occupied until the third year. Hanging houses in the fall or winter might increase the probability of occupancy in the first active season. If a house is not occupied by the end of the second year, you might change its location.
What types of bats are most likely to use a bat house?
Throughout the northern two-thirds of the United States and into Canada, the little brown bat (Myotis lucifugus) and the big brown bat (Eptesicus fuscus) are the most prevalent. These species also occur in the southeastern United States, but in the Gulf states the southeastern bat (Myotis austroriparius) and the Mexican freetailed bat (Tadarida brasiliensis) are the most common. In the southwest and western United States, the Mexican freetailed bat and a variety of small bat species (often loosely referred to as mouseeared bats may occupy bat houses. Pallid bats (Antrozous pallidus) may also roost in bat houses, especially in arid areas. In general, any species that naturally roosts in crevices or is known to roost under bridges or in buildings is a likely candidate for a bat house.
How can I attract bats to my bat house?
Bats find bat houses just as birds find birdhouses. If roosts are needed in your area, and your bat house is appropriately located and meets bat requirements, bats eventually will find it and move in on their own. Some people have painted the inside of bat houses with moistened bat droppings to establish a bat odor, but no one is certain that this makes houses any more attractive to bats.
Most North American bats apparently prefer to live within a few hundred yards of water, especially streams, marshes or lakes, although colonies are sometimes found up to a mile or more from such places. In some western areas, they may travel several miles, utilizing only a cattle trough or some other small water source. Wherever bats live, they must find enough insects to eat, which largely explains their preference for aquatic habitats. In urban areas, the oldest neighborhoods, with their larger trees and more-established yards, are the most apt to meet bat needs.
