Bats

Did you KNOW??
Research has shown that bats can consume up to 1,000 mosquitoes in an hour!

Our Four-chamber Bat Nursery House is the result of a unique partnership between RCD and Willows High School Woodshop students / Future Farmers of America. Another project in RCD Connects with Kids! Local students have carefully constructed our Bat Houses. By purchasing and installing one of our Bat Houses, we may, together, promote bat populations for the benefit of our natural resources and your operation, or home, while providing an educational opportunity for students to learn how to handcraft a nesting box. Students learn how to read design specifications, build a product, perform Quality Control using a specialized form for this product, as well as earn some money while doing so!

Many people have serious misconceptions about bats… but bats are good! Myths include they are vicious carriers of rabies and they are a pest which is abundant. The fact is that bats are actually harmless and are very important indicators of a healthy environment. Bats tend to be sensitive to high pollution and pesticide levels, so they are useful as a warning sign to potential environmental problems. Bats can also be important weapons in combating insects that are actually dangerous to humans.

  • A small bat can capture up to 1,000 mosquitoes in a single hour!
  • Bats cannot contract the West Nile Virus by eating infected mosquitoes.
  • Besides mosquitoes, bats can help control the populations of beetles, moths and leafhoppers.
  • Many insects can hear bats up to 100 feet away and will avoid those areas occupied by bats.
  • The effectiveness of bats in some areas diminishes the need for pesticides that can potentially harm both pests and their natural predators.

TEMPERATURES:
Maintaining proper roost temperatures is probably the single most important factor for a successful bat house. Interior temperatures should be warm and as stable as possible (ideally 80º F to 100º F in summer) for mother bats to raise their young. Some species, such as the big brown bat, prefer temperatures below 95º F, while others, such as the little brown bat, tolerate temperatures in excess of 100º F. Bachelor bats are less picky and may use houses with cooler temperatures. The sides of wooden or masonry structure are the best mounting sites, especially in colder climates, because temperatures are more stable than in the houses attached to poles.

Bat house temperatures are influenced directly by the exterior color, compass orientation (east-, southeast-, or south-facing are generally good bets for single houses in most climates), the amount of sun exposure, how well the house is caulked and vented, and the mounting and construction materials. You may have to experiment on the placement of the houses to get the right placement and temperature range. You can always use a thermometer taped to a pole to see if temperatures are suitable inside the bat house (check the chambers high and low, and front and back).

INSTALLATION SITES:
Pick installation sites with care so you don’t have to move it after it is occupied. Most bat houses have open bottoms, which keeps guano from accumulating inside. Guano will, however, end up on the ground underneath, so avoid placing bat houses directly above windows, doors, decks or walkways. Bat urine may stain some finishes. Two- or four-inch spacers between a bat house and the wall, a large backboard or a longer landing area below a bat house may reduce guano deposits on the wall. A potted plant or a shallow tray or plant saucer can be placed underneath a bat house to collect bat guano for use as fertilizer in flower beds or gardens. Do not use a bucket or deep container (unless 1⁄4-inch or smaller mesh covers the entire top of the container), as any baby bats that fall from the bat house could become trapped inside.

Both single and multi-chambered bat houses work well when installed on buildings. Wood, brick or stone buildings with proper solar exposure are excellent choices, and houses mounted under eaves are often successful. Bat houses mounted on buildings with metal siding are seldom used. All bat houses should be mounted at least 10 feet above ground, but 12 to 20 feet is better. Choose a sunny location on the east or south facing side of your house. Bat houses work best with at least 6-8 hours of direct sunlight (if only partial day sun is available- morning sun is preferable). Bat houses should not be lit by bright lights, so installing near porch or security lights is generally a bad idea. Do not install your bat house above doors or windows where guano will fall or accumulate in an inconvenient location.

Bats may find bat houses more quickly if they are located along forest or water edges where bats tend to fly. However, they should be placed at least 20 to 25 feet from the nearest tree branches, wires or other potential perches for aerial predators. Most nursery colonies of bats choose roosts within 1/4 mile of water, preferably a stream, river or lake. Greatest bat-house success has been achieved in areas of diverse habitat, especially where there is a mixture of varied agricultural use and natural vegetation. Bat houses can be installed at any time of year, but they are more likely to be used during their first summer if installed before the bats return in spring. When using bat houses in conjunction with excluding bats from a building, install the bat houses at least two to six weeks before the actual eviction, if possible. It is best to test for local needs before putting up more than three to six houses. Compare houses of different colors and/or different levels of shade and sun exposure.

MAINTAINING YOUR BAT HOUSE:
Once you have attracted bats, you must maintain the bat houses to keep bats coming back year after year. Wasp and mud dauber nests should be cleaned out each winter after bats and wasps have departed. New caulk and paint or stain may be required after three to five years to guard against leaks and drafts. Bat houses should be monitored at least once a month (preferably more often) to detect potential problems such as predators, overheating, wood deterioration, etc. Any repairs or cleaning should be performed when bats are not present.

Four-chamber Bat Nursery House in Glenn County rice field

“Backside” of Four-chamber Bat Nursery House in Glenn County rice field