Mounting a bat house on a dedicated pole is the most effective installation method for attracting a colony. This technique offers significant advantages over attaching the house to a building or a tree by reducing access for ground-based predators like raccoons and snakes. A pole installation allows precise control over height, solar exposure, and proximity to obstacles, which strongly influence the success of a bat house. This guide outlines the necessary steps to successfully install a freestanding bat house on a pole.
Choosing the Best Location and Pole Type
Successful bat house placement relies on maximizing solar gain and ensuring a clear flight path. The location should allow the house to receive at least six to eight hours of direct sunlight daily, with a south or southeast orientation being best to capture morning warmth. This orientation helps maintain the high temperatures (85°F to 100°F) bats require for raising their young. The house must be mounted a minimum of 12 feet off the ground, with 15 to 20 feet being preferable, and positioned where bats have a clear, unobstructed drop zone of at least 20 feet below the entrance.
A freestanding pole offers flexibility, allowing placement away from overhanging tree branches or utility wires that aerial predators like owls and hawks might use as perches. When selecting a pole, galvanized steel pipes or heavy-duty, pressure-treated wooden posts are the primary options. Metal poles, often two-inch diameter galvanized steel, offer superior durability and weather resistance, though they may require specialized U-bolts for attachment.
Treated wooden posts, typically four-by-six inches or larger, are easier to attach using lag screws and mounting brackets. While wood is susceptible to rot and insect damage, laminating two smaller pieces of lumber together can increase stability and resist warping. The pole provides necessary isolation from climbing predators, which is often lacking when houses are placed on trees.
Pre-Installation Assembly and Materials
Before beginning the groundwork, all necessary hardware and the bat house should be prepared. Essential materials include the pole, the bat house, a post-hole digger, fast-setting concrete or pea gravel, a level, mounting hardware (such as heavy-duty lag screws or bolts), and a sturdy ladder. For wooden posts, attach the primary mounting blocks or brackets to the back of the bat house first.
Pre-drilling pilot holes into the mounting hardware and the bat house backing prevents the wood from splitting when the lag screws are driven in. This ensures a secure connection and prevents hardware from protruding into the internal roosting chambers, which must remain smooth and clear for the bats. If using a large, multi-chambered house, consider affixing the mounting brackets to the pole while it is horizontal, especially if the house is too heavy to maneuver at full height.
Step-by-Step Pole and House Installation
The first step is digging the hole for the pole, which must be deep enough to provide stability. For a 16-foot pole, the hole should be at least 30 to 36 inches deep and approximately twice the diameter of the pole. Ensuring the hole is straight and the bottom is tamped level helps the pole stand securely while the setting material is added.
Once the hole is prepared, set the pole and orient it so the mounting side faces the desired direction, typically south or southeast. The pole is then secured using tamped soil, pea gravel, or concrete. If using concrete, an 80-pound bag of premixed concrete is usually sufficient for a single post hole, with water added and mixed directly in the hole.
Check the vertical stability on all sides with a level before the concrete cures, bracing the pole with temporary supports if needed. Allowing the concrete to cure for the manufacturer’s recommended time is necessary for a stable foundation that can withstand wind and the weight of a full colony. For wooden posts, using pea gravel instead of concrete is suggested to minimize moisture retention and potential post rot.
Securing the bat house to the stable pole is the final major task, often requiring multiple people for safety and leverage, especially with large houses. The house is lifted to the desired height and secured with heavy-duty bolts or lag screws through the pre-drilled holes in the mounting brackets. Fasteners should be tightened firmly to prevent movement, which could deter bats from colonizing the structure.
A predator guard is necessary to protect the colony from climbing terrestrial animals. This involves installing a smooth, galvanized metal sleeve or cone around the base of the pole. The guard should be placed at least three feet above the ground and extend upward for two feet or more, preventing raccoons or snakes from gaining a foothold and climbing the pole.
Monitoring and Post-Mounting Care
After installation, a short period of initial monitoring ensures the pole and house are stable. After a few days, a visual inspection should confirm that the attachment points have not shifted and that the pole remains plumb, especially if fast-setting concrete was used. Confirming the house is secure prevents accidental detachment, which would cause the colony to abandon the roost.
Long-term care involves checking the exterior of the house for signs of weathering, such as cracks or joint separation, which can compromise internal temperature stability. The exterior seams of wooden houses may need periodic inspection and resealing with exterior-grade caulk, usually every few years. The house should also be checked for wasp nests, which can be removed during the winter or early spring before bats arrive.
If a bat colony successfully occupies the house, avoid cleaning or disturbing the house, as bats require specific environmental conditions and may abandon the roost if they feel threatened. Signs of success, such as guano accumulation beneath the house, indicate that the habitat is working as intended. The longevity of the installation depends on maintaining the structural integrity of the pole and the thermal efficiency of the house.