The bat house was a low priority project I thought about for years. It was fun to finally get it done. The house is big; it should accommodate somewhere around 300 bats.
Bats are beneficial in the yard and garden but not in your house. Bats eat large numbers of flying insects and we have plenty of those.
Bats thrive mainly on insects; you can call them insectivores. They love to eat flies, mosquitoes, moths, beetles, wasps, dragon flies, and other insects.
Researchers and scientists have posited that a bat can eat 600 to 1,000 mosquitoes and other insect pests in just one hour. And nursing mothers will eat even more than other bats!
A fungus grows in bat guano that releases toxic spores when disturbed. Breathing the spores causes histoplasmosis, which makes you sick for a couple of weeks. The disease can invade the central nervous system and may be the source of the term bat shit crazy.
I have found small amounts of guano in the barn. They may not like it in there. I've read bats don't like metal buildings.
Because of that, I decided not to mount the bat house on the barn, which was my original plan. Instead it will be mounted on a 16' 6x6 cedar post set in concrete.
The location we chose is in the middle of a bunch of lilac bushes near the barn. Most of the nitrogen-rich guano should land in the bushes, where people aren't likely to walk. Also, being outside reduces the risk of breathing the toxic spores quite a lot.
The post is currently on order; it should arrive in about ten days or so. I will add pictures when the bat house is up and ready for bats.
Materials were mainly one 4x8 sheet of 1/2" plywood and one 8' 1x6. There was enough plywood to make the roof but I had a left over piece of 1x12 face cedar that I used instead.
There were also a small number of screws, a tube of construction adhesive, a few square feet of 3/4" styrofoam insulation, and a can of spray foam insulation.
Some square head bolts were left over from the fence. They added a touch of iron to the front, sides, and back.
The black iron handles were ordered with the iron trim for the gate columns. They were too dinky for the columns and the finish was crusty, which was great for the bat house. The rust should weep in the rain and create long dark streaks down the wood below the handles.
We had enough stain to cover the bat house, inside and out, left over from the fence, swing, and mailbox. There's still plenty of stain to cover the post for the bat house.
As luck would have it, the manufacturer of the cannonball post caps sent an extra one, when we ordered them for the fence, swing and mailbox. It will be placed on top of the bat house post.
Polite comments are welcome.