Don’t Love Mosquitos? Then Show Some Bats a Little Love

— Written By and last updated by

The end of October is spooky Halloween-Time, but with increased fall rain and warm temperatures it can still be mosquito time. Mosquitos can be annoying when their blood-sucking activity during twilight hours and at night interferes with outdoor activities like Trick or Treating. They also can transmit disease organisms to people and domestic animals. Pesticides are only a short-term solution to nuisance mosquito problems. So where do Bats come in?

They can be your Halloween-Heroes. Bats are the only major predator of night-flying insects. Their diet includes lacewings, cockroaches, gnats, beetles, moths, and mosquitos. A single Big Brown Bat can eat between 3,000 and 7,000 mosquitos in a night, with large populations of bats consuming thousands of tons of potentially harmful forest and agricultural pests annually. Our state supports 17 species of bats, including four federally listed as threatened or endangered.

Instead of fear induced persecution, these garden warriors deserve an invitation. Providing both foraging areas and roosting locations is essential. Bats spend over half of their lives in roosts and rely on sheltered, undisturbed sites such as caves, crevices in rocks, and tree cavities to meet their needs. In the winter months, insulated roosts are important for hibernating bats, while in late spring and early summer, roosts that can sustain daytime temperatures between 80 and 90º F are important for raising young bats. Encourage bats on your property by creating all components of bat habitat in close proximity. Maintain and manage snags in mature woodlots to increase the availability of cavity roosts. Install properly constructed artificial roosts in areas were natural roosts are scarce or absent.

Construction Tips:

  • Use cedar, cypress, or pressure-treated pine lumber to insure durable, longer-lasting boxes.
  • Use rough lumber, cut shallow grooves, or attach fine plastic or wire mesh to the inner surfaces of the box so bats can easily crawl up and into the house.
  • Avoid painting or varnishing the inside of the house.
  • Use darker paint on the outside of the box for high temps needed.
  • Seal all seams with silicone caulk to waterproof houses and prevent heat and moisture losses.

Installation Tips:

  • Place bat boxes close to rivers, lakes, ponds, marshes, etc..- permanent water sources where the insects are.
  • Mount boxes 10 to 15 ft off the ground on posts made of metal or wood and away from overhanding tree limbs. Attach predator guards of roofing tin on the mounting post at a height of 3 ft to protect roosting bats from house cats, raccoons, and snakes.
  • Tilt houses at a 10 º angle to help young bats stay in the box.
  • It may take up to two years for bats to find and begin using artificial roosts.

For step by step instructions with pictures, look at Build a Bat House and make a Halloween Hero memory with your family this year!

Minda Daughtry is Horticulture Agent for North Carolina Cooperative Extension in Lee County.