Just the thought of them can send shivers down the spine of even an ardent not-so-squeamish human. Why then, you ask, would somebody want to attract those winged creatures of the night to one's backyard by placing a bat house?
Bats are among the least understood animals. The uninformed have bestowed upon them all sorts of evil traits, most of which are untrue. In reality bats are very beneficial to our increasingly delicate environment.
Sure, once in a while they wiggle through tiny cracks or crevasses into our homes and frighten us as they expertly dodge tennis rackets, brooms, and other "weapons" while zigzagging from one room to the next. But bats also eat insects, and lots of them. Studies show a single bat may eat as many as 5,000 mosquitoes in one night. Who is responsible for counting bat-eating insects I'm not sure, but even if they devour one-tenth that many biting bugs, good for them. For that, we should provide them with a home.
Bat houses are available from most stores that sell bird houses and bird feeding products, or you can build your own. Carrol Henderson, Minnesota DNR nongame wildlife supervisor, has written an excellent book titled Woodworking for Wildlife. The book includes simple plans for building two different styles of inexpensive bat houses. Plans to build a large, Missouri-style bat house are also available from the DNR nongame.
There are several factors to consider when placing a bat house:
1. Your bat house should be situated to receive maximum solar radiation, especially in the morning. It should face east to absorb the morning sun yet be shaded from the blazing heat of the afternoon.
2. Mount the house at least 10 feet high under the eaves of a house or garage or in a tree sheltered from the elements.
3. If your bat house is not occupied by the second year, try a different location, or place more than one house initially.
4. If you live near a pond, lake or river, your chances of success are increased because bats need a source of water for drinking purposes. However, don't be discouraged if the conditions are not perfect.
Will bats already living in your attic move to a properly placed bat house? Not likely, unless you close access to your attic when they leave to feed at night or during the winter when the bats have migrated.
Despite their unattractive appearance and bad reputation, bats provided me with one of my most memorable outdoor experiences. I was bow hunting for deer in early September not far from the bat house that hangs under the eave on the side of my house. From my perch in an ash tree I watched as the sun set over a pond -- the afterglow a radiant yellow-orange -- when a great horned owl flew from the depths of the mostly-green forest and landed atop a dead tree. Moments later several bats appeared. The winged mammals flew randomly about during their insect gathering forays, and the owl followed their every move, its head swiveling back and forth signaling its intent.
"No way," I thought. "A large, cumbersome great horned owl would not have a chance at capturing a radar-equipped bat on the wing."
Suddenly the owl sprang from its perch. The big bird-of-prey flew directly upward toward its intended target -- a bat winging a few yards above its head. I watched in amazement as the predator/prey confrontation unfolded silhouetted against the brilliant orange sky. Upon reaching its intended victim the owl swung its large feet upward and with needle sharp talons, snatched from below the clueless bat.
The owl returned to its original perch where it downed the bat in one gulp. Three times the owl repeated the performance.
Reason enough for me to provide a home for bats.
Bill Marchel, an outdoors photographer and columnist, lives near Brainerd.