Installing a bat house is a popular and practical method for homeowners seeking natural pest control and supporting local wildlife conservation. These specialized roosts offer a substitute habitat, which is increasingly necessary as natural roosting sites decline due to changes in building standards and land management practices. Bat houses are an effective strategy across North America for attracting colonies of insect-eating bats. The presence of a successful bat house can provide a clear benefit to the immediate environment.
Primary Benefits of Attracting Bats
The most compelling reason for installing a bat house is the significant reduction in insect populations around your home and garden. Many bat species are insectivorous, meaning they feed exclusively on night-flying insects, which provides free pest control. A single bat can consume up to half its body weight in insects each night.
This voracious appetite targets common garden and agricultural pests, including mosquitoes, moths, cucumber beetles, and corn earworms. A colony of just 150 big brown bats can eliminate tens of thousands of damaging insects over a summer season. Beyond pest management, providing a safe roosting site aids in conservation efforts, as many bat populations are facing threats from habitat loss and disease.
Essential Requirements for Successful Installation
The success of a bat house depends almost entirely on its placement, as bats are highly selective about their roosting conditions. The structure must be mounted high off the ground, ideally between 12 and 20 feet, to deter predators and allow bats a clear flight path. It is also important to position the house in an open area, free from obstructions like tree branches for at least 20 feet below and in front of the entry point.
Solar exposure is the single most important factor for attracting a maternity colony, as female bats need high internal temperatures, often exceeding 85°F, to raise their young. The bat house should receive at least six to eight hours of direct sunlight each day, with a south or southeast orientation often being recommended. To maximize heat absorption, especially in cooler climates, the exterior of the house should be painted a dark color using a water-based exterior paint.
Mounting the house on a pole or the side of a building is generally more successful than mounting it on a tree, which can provide too much shade and allow easy access for predators. Furthermore, a location near a permanent water source, such as a pond or stream, is highly beneficial, as bats drink at dusk and feed heavily on insects that congregate near water. The house should also be situated at least 10 to 15 feet away from any tree line.
Addressing Safety and Health Concerns
Concerns about human and pet safety are understandable, but the risks associated with backyard bat houses can be managed with knowledge and precaution. Rabies is the most commonly discussed health hazard, though less than one percent of bats tested are infected. It is important to remember that any mammal can carry the virus, and bats should never be handled directly, especially if they are found grounded or behaving unusually.
Another consideration is histoplasmosis, a respiratory disease caused by inhaling spores from a fungus that grows in accumulated bat guano. While small amounts of guano pose little risk, the house should be placed away from high-traffic areas like patios or walkways to prevent accumulation. When cleaning up guano, especially large, dry deposits, individuals should wear a properly fitted respirator and wet the material down before removal to prevent spores from becoming airborne.
What to Expect After Installation
Patience is necessary after installation, as bats are cautious and may take considerable time to investigate a new roost. It is common for a bat house to remain unoccupied for a year or more, and in some cases, it may take up to five years for a colony to establish itself. Success is more likely if the guidelines for height, sun exposure, and location near water are meticulously followed.
Once occupied, the house requires very little maintenance, which should only be performed when bats are absent, typically in the late fall or winter. Annual checks can be used to ensure the structure’s seams are tightly sealed to retain heat and to remove any abandoned nests from wasps or other insects. Failure to attract bats is often due to insufficient heat, poor placement leading to predator access, or a design that lacks the necessary features like a rough interior and proper chamber width.