Build Bat Boxes

Bat boxes were designed to help with the recovery of endangered bats, an essential predator for controlling insects.

| March/April 1981

068 bat boxes - diagram 1

Diagram shows the first of two proposed bat box designs.


People who reside near rivers, swamps, lakes, or ponds can usually expect high insect populations. But, if they're lucky, such folks will discover that the bugs are kept in check by local colonies of bats ... which swoop out of their roosts each evening and locate their pesky prey with remarkably precise "radar" systems (echoes of their high-pitched squeaks return to them whenever the sound waves encounter solid objects). During the summer months, bat colonies consume mosquitoes, gnats, moths, and beetles, thereby playing essential roles in the ecosystem. In fact, some of the little predators eat as much as half their body weight in insects each night! 

A War of Ignorance

Unfortunately, however, these nocturnal hunters aren't seen in the night skies as often as they were some 35 years ago because they've suffered, as many insectivorous (and other!) birds have, from the effects of DDT. And though this deadly pesticide has been banned from general use in the United States since 1972, it's sometimes still, illegally, dumped into attics as "bat control" (although the poison probably endangers the human occupants of treated residences almost as much as it does the winged population it's meant to kill or evict).

Furthermore, as if residual DDT (and the continuing "outlaw" use of the chemical) in the United States weren't bad enough, bats have no awareness of national borders. The Carlsbad Caverns' bat population decreased from an estimated 8.7 million in 1936 to 200,000 in 1973, and is still being reduced as a result of the mammals' annual migration to Mexico, where DDT is still in regular use.

While many bats fall to such poisons, others are prey to the deeply ingrained fears and misunderstandings of humans who wantonly destroy their roosts or carelessly disturb the animals in their hibernation caves. The latter action can be particularly harmful, because — when hibernating — bats fall into a deep torpor and live off small reserves of stored fat. If they're aroused unnecessarily, the animals use up their "rations" too rapidly, and may well starve in their sleep before the spring awakening.

So far, three bat varieties are on the U.S. endangered species list, two more have been proposed for listing, and still others are probably in need of protection. (Being on the list doesn't insure the survival of a species, but does provide some habitat protection.) Bats that may shortly become extinct are the Indiana ( Myotis sodalis ), the Gray ( Myotis grisescens ), the Hawaiian Hoary ( Lasiurus cinereus semotus ), the Virginia Big-Eared ( Plecotus townsendii virginianus ), and the Ozark Big-Eared ( Plecotus townsendii ingens ).

"Bad Press" Victims

In the Western world, bats — although they are, for the most part, harmless and may well be the most effective natural insect controls in existence — have long been feared. This human reaction probably stems from the fact that medieval artists often attached bat wings to figures representing devils and demons ... as well, of course, as from the animals' connection with the Dracula legend.

dairy goat


Aug. 5-6, 2017
Albany, Ore.

Discover a dazzling array of workshops and lectures designed to get you further down the path to independence and self-reliance.