They are common in wetland areas with heavy mosquito population. Encouraging an active bat population is an extremely effective way to control mosquitos. They come flying out of these bat houses at dusk and gorge themselves.

One of the largest bat houses in the country is at Spirit of Suwannee Music Park, a music festival venue in the wetlands of north Florida built right on the Suwannee River. Obviously insanely fertile ground for mosquitos, but this bat houses holds 30,000-50,000 bats which keep the mosquitos under control. It’s an insane sight, watching them all pour out of there for like 5 minutes straight right at dusk every night.

Check this out

While @AugustWest@lemmy.world provides an anthropogenic use for bat boxes, they are widely used in conservation.

Disturbance is putting a lot of pressure on bats. White nose fungus is also hammering bat populations. Anyway, bat boxes are artificial refugia - simulated habitat. These boxes, like other artificial refugia, such as bee boxes, need to be pretty carefully designed so they don't do the following:

• thermally stress the animals - they won't use them, or they'll die if they freeze or fry in them
• act as traps - predators are smart, and will exploit poorly designed refugia
• promote disease, in the case of bee or bat boxes - refugia can be any shape or size, but ones that encourage multiple animals to use them can cause mortality through spreading disease

In general, refugia are at best temporary spaces while ecosystems recover from disturbance and natural habitat re-establishes. This is hard in the case of bats, because they need tree crevices (found in older trees) or rock outcrops and the like.

there's some really cool papers out there on artificial refugia, if you want to nerd the fuck out about it. Cowan, did some great work around them. He's a cool dude, and was super pumped to hear how his papers were being considered from a reclamation standpoint when I reached out to him: https://conbio.onlinelibrary.wiley.com/doi/10.1111/csp2.204