Mount your bat house in an open area so the bottom is fifteen to thirty feet off the ground. The area in front of the bat house should be clear of trees. Bats need a "swoop zone" and nearby obstacles such as tree branches reduce sunlight and may interfere with bats' flight patterns. Bat houses should not be placed near tall trees that might provide a convenient perch for predators such as owls and hawks. The presence of such a perch will discourage bats from moving in to your bat house.

The side of a two-story building is the easiest choice. The bat house should be set out from the building an inch or two on small pieces of wood to ensure that droppings do not soil the side of the building. The bat house should not be mounted over windows, doorways, decks or walkways. It should not be shaded by an overhanging roof. Some experts suggest tilting the bat house out slightly at the bottom (10 degrees or less) to help prevent baby bats from falling out.

Free-standing poles are an ideal choice for mounting a bat house. A variety of poles are available at local hardware stores. Caribbean Utilities Co Ltd (CUC) asks, for reasons of safety, that bat houses NOT be mounted on their poles that are being used to carry electricity.

Mr. Ron Moser has designed a very strong method of joining two bat houses back-to-back and samples of this method can be seen throughout Grand Cayman on utility poles donated by Caribbean Utilities Co Ltd (CUC) to the National Trust Bat Conservation Programme. CUC donates a set number of these poles each year, and they are placed in the locations that are most likely to be successful in attracting bats. You may qualify for the use of one of these poles. Contact the National Trust to discuss your project with the director of the programme.

Guano, or bat droppings, will collect under the bat house and can be mixed with soil to make a very good fertilizer. Do not use full-strength unmixed guano or you may "burn" the plants. These droppings are dry and harmless, but as with any animal droppings, do not breathe the dust when working with them.

Finished bat houses are for sale at the National Trust and free plans are available for those who would like to build their own.

When your bat house becomes inhabited, (usually in November) please tell the National Trust. Bat houses are still experimental in the tropics and your information is needed. You can count the bats as they leave just at dusk each evening.

KEYHOLE METHOD
1. Cut a "keyhole" in the back of the bat house with two different-sized drill bits. The bottom of the hole should be the exact size of the bolt you are using and the top section should be the exact size of the shaft of your bolt.
2. Screw the bolt into the side of the building, leaving about half an inch protruding.
3. For a masonry building, use masonry screws called quarter-inch tapcon or a lag bolt and shield. For a wooden building, use galvanized deck screws.
4. Push the bat house on to the bolt through the larger bottom half of the keyhole. Pull it down, securing the smaller top half around the shaft of the bolt.
5. Secure the bat house on the bottom by screwing through the landing pad.

BRACKETS
Brackets can be screwed to the back of the bat house, or a piece of one-by-four or two-by-four board can be used as a bracket. Be sure to use the proper size screws, so that no sharp points intrude inside the bat house to tear the bats' delicate wings.

ON METAL POLES
Poles can be purchased from local hardware stores. The most economical poles we found were 20-feet by 2-inch metal poles from A.L. Thompson's for about $40 each. Two of these poles can support a bat house, but it is recommended that if using poles, two bat houses be mounted back-to-back on them. This provides more temperature choices for the bats and the space in between the two bat houses can be covered with netting, screen or roughened to provide an additional crevice for the bats to use. A roof can be put over both bat houses to create the look of a single unit.
Poles should be buried in cement that is several feet deep.

UTILITY POLE
CUC has been very generous in donating poles to the bat conservation programme. These poles are usually placed in areas visible to the public and accessible to CUC's equipment. They are not usually available for private gardens, but exceptions have been made. Sometimes wires have been removed from existing poles and bat houses can be placed atop them. Check with the Trust if you think you have a usable pole in your garden.