Source: Doug E Mayo, University of Florida Panhandle News

Oct. 26, 2013 — Bats are voracious feeders. Beyond eating mosquitoes, there is a definite advantage in having them on your property during the row crop season. Their food of choice is a wide variety of night-flying insects, many of which are the adult stages of crop pests.

Among the many different species of bats, there is the Brazilian free-tailed bat, evening bat, big brown bat and southeastern bat, all of which are known to consume some of the most destructive pests to corn, cotton, pecans and people, including:

  • corn earworm
  • fall armyworm
  • cabbage looper
  • tobacco budworm
  • pecan nut casebearer
  • hickory shuckworm
  • green stinkbugs
  • mosquitoes

Proactively Attract Bats

All four of the bat species most likely to consume insect pests typically prefer to roost in man-made structures such as bridges, attics, stadiums, picnic shelters, barrel tile roofs and bat houses. This is great news because small bat houses are easy to build and the materials required are fairly inexpensive.

Also, pre-made bat houses can be purchased at many gardening stores or online. But beware that many pre-made houses will not attract bats because of poor design or construction. Below are the characteristics that distinguish good bat houses from the rest:

  • Roost chambers should be a minimum of 20 inches tall
  • Roost chambers should be at least 14 inches wide
  • Roost partitions should be spaced 3/4 inches apart (1 inch is appropriate in South Florida)
  • A 3- to 6-inch landing pad should extend below the entrance to facilitate movement of bats in and out of the house
  • Interior surfaces and landing areas should be rough to provide footholds for bats
  • Sharp objects such as screws, staples, nails, and mounting hardware should not protrude into the roost chambers
  • ½-inch tall ventilation slots should be provided no more than 1/3 the distance from the bottom
  • Chemically-treated and pressure-treated wood should not be used.  Boards of cedar or pine are appropriate. Plywood should be exterior grade (e.g. ACX, T1-11, BCX)
  • All exterior joints should be caulked or sealed to prevent drafts or leaks

Consider The Location

Bat houses are most likely to be occupied when mounted on a post or the side of a building: not on a tree. When mounted in a location exposed to sunlight all day, houses should be painted a light color so that some heat from the sun is reflected.

When mounted in a location that receives little sunlight, a medium brown works well so that some heat from the sun is absorbed. Bat Conservation International lists specific vendors in each state who sell bat houses with these characteristics preferred by bats.