"Rocket Box" in Kentucky

In our work in the Daniel Boone National Forest in Kentucky, John MacGregor and I have been experimenting with a simple bat house design nicknamed the "Rocket Box." The house is basically a covered box that slides over a wooden post inserted in the ground (see diagram). Sixty boxes have been placed in a variety of forest, riparian, and urban habitats. Our best success rate (100%) is with boxes located on ridgetops in prime habitat. About 75% of boxes placed along riparian habitats were used last year, and about 50% of boxes in mixed riparian and urban habitats were used. Use was very low in pure urban areas.

Rocket boxes are designed to be similar to trees with exfoliating bark, one of the most commonly used natural roost sites. Bats can move freely within this design to either cooler or warmer sides of the structure depending on their needs. If predation becomes a problem, predator guards can be added to the 4x4 post.

When building a rocket box, avoid using treated lumber or soft woods for the 4x4 post, since these could be harmful to bats or could decay quickly in the ground. The box itself can be made of a lighter wood since it is not in direct contact with the ground and is partly covered by the roof. Use only galvanized screws to put the bat box together. If you can get the post in the ground at least two-and-a-half to three feet, there is no need to cement it in, although concrete may deter termite damage. Spacing between the bat box and the 4x4 post is critical. Any more than three-quarters of an inch will make it more attractive to mud daubers and paper wasps.

Bats moved into some of these houses in as little as two weeks after installation. Single houses have sheltered up to 15 bats of at least two species, northern long-eared myotis (Myotis septentrionalis) and big brown bats (Eptesicus fuscus). Many bats have been observed in the bat houses but could not be identified due to the long narrow shape of the house.

We had our best results when the bat houses were located in upland forest habitats on south or southwest slopes with open canopy. They did well in small openings along forest roads and rights-of-way where they receive more sunlight. We did not place many bat houses close to buildings, and have not painted any of the houses, although caulking and painting could help.

For plans, or more information, contact Dan Dourson, Stanton Ranger District, Daniel Boone National Forest, U.S. Forest Service, 705 West College Avenue, Stanton, Kentucky 40380, (606) 663-2852.

Screened vent 1/2" to 3/4" in diameter*
Additional cuts could be made to increase roosting area
Cut top of 4x4 post at a sharp angle and roughen. This is the area where most bats will roost.
Slightly round off post corners.
3/4" spacer (wood block). Use lag bolts to attach box to 4x4 post.

*Although this bat house has been successful in Kentucky, we suspect that most houses will meet bat needs better if equipped with lower vents. Side-by-side testing comparing different location of vents is planned.
Courtesy of Dan Dourson and John MacGregor, Daniel Boone National Forest.