“Put your box somewhere that won’t be developed,” says Kent Borcherding, a retired cheesemaker from Hazel Green, Wis., who has built more than 800 bat boxes, including dozens for state parks and historic sites. Bats need a warm, safe place to sleep during the day. By providing one, you become a bat landlord of sorts, which you should think of as a long-term commitment: Bats can live more than 40 years, and their babies return to where they were born. Borcherding is still monitoring boxes he built over 25 years ago. Don’t be a slumlord. “Build it to last,” says Borcherding, who uses hardwoods like white oak and black locust, exterior-grade screws and high-quality caulk to seal moisture out.

Boxes should be at least 24 inches across and 30 inches tall and contain multiple chambers inside, which you’ll make using wooden partitions spaced about three-quarters of an inch apart (bats like to squeeze together in tight places). Borcherding suggests that first-time builders refer to detailed diagrams available online from Bat Conservation International. To ensure that the bats can cling to the boxes, use rough-hewed wood or score your boards with a knife. If you live in a colder climate, paint the exterior of the box with a dark color so it retains more heat. Bats will enter from the bottom, which you should leave open. The box’s back wall should be 2 to 4 inches longer than the front, providing a landing pad from which bats will crawl up into the darkened chambers. Affix your box to a pole or a house (not a tree) in a sunny spot about 10 to 20 feet off the ground.

Before spending half a day building a habitat for bats, you will, of course, need to find them worthy. For Borcherding, that’s the easy part. “I tend to root for underdogs,” he says. If you need other reasons, he will talk breathlessly about their sophisticated echolocation; or their insect-eating prowess (some can eat as many as 1,000 mosquitoes in a night); or the simple fact of their beauty, especially the sight of them rushing en masse back to their roosts before daybreak, a phenomenon called dawn swarming. “It’s really something to see,” he says.