Where should we locate our bat house?—Al Dobson, via email
Think like a bat. Your only goal is to survive and reproduce. You need access to water; you need safety; and you need a good place to raise your babies. You’ll choose your home accordingly.
Most bat conservation organizations recommend locating a bat box somewhere close to natural water (within 1,500 feet) but not too close to any treeline (at least 20 feet away). Thick stands of trees can make bats nervous; all those branches give predators plenty of places to hide.
Bats—especially females—like warmth. “So, an east-facing location is probably best,” says Robert Barclay, a professor of ecology and evolutionary biology at the University of Alberta. “The box will warm in the morning but not cook from the sun in the afternoon.” If a lady bat deems a box too cold, she’ll refuse to nest there. And that’s no good; the children are the future! No, really. One bat eats 1,000 mosquitoes per night. Cottagers need them.
You can certainly attach a bat house to the side of your cottage. “The higher up the better,” says Barclay. Bats returning to the house need enough space to swoop down and then up into it. And baby bats, learning to fly, need room to briefly free-fall before they get their flapping under control, or else they’ll just crash to the ground. Barclay recommends positioning the box at least 15 feet up. But, “choose the location wisely,” he says. Bat feces are going to drop below the box. Over a flower bed is fine. Over a walkway or patio is ew.
Bats tend to avoid houses mounted on trees, or on structures with metal siding, according to Bat Conservation International. Another option is to mount the box on a pole. This may give you the flexibility to position it where it’s going to be most beneficial to your bat friends…and in the end, you.