A&M-KINGSVILLE GOIN' BATTY
(KINGSVILLE, Jan. 27, 1997) -- When Oscar Castillo became physical plant director at Texas A&M University-Kingsville he never imagined that part of his job description would include building houses for bats. He'd probably have thought, that's well, ... batty.
But ridding the Student Union Building (SUB) of the pervasive odor of the bats that have taken up residence under the roof tiles has led him to become an expert on the construction of bat houses. Castillo learned that at least one species of bats found on campus, the Southern yellow bat, is considered threatened in Texas, and that Mexican free-tailed bats, the most common species on campus, are beneficial because they eat insects. That meant removing the bats from the SUB had to mean relocating rather than exterminating them.
The Mexican free-tailed bat is the same species that lives in Carlsbad Caverns and under the Congress Street bridge in Austin, said Associate Professor of Biology Steve Smith. The Austin bat colony, with up to 1.5 million bats in residence from March to November, is considered the largest urban bat colony in North America and has become a tourist attraction. On the nightly flights out from under the bridge, the Austin bats eat from 10,000 to 30,000 pounds of insects, including mosquitoes and numerous agricultural pests, according to information from Bat Conservation International. The Mexican free-tailed bats sometimes fly up to two miles high to feed or to catch tail-winds that carry them over long distances at speeds of more than 60 miles per hour.
Smith said bats pose little threat to people who do not handle them. Although they can carry rabies, fewer than one-half of one percent do, he said. Any bat you can catch, however, is more likely than others to be sick and should not be handled, he emphasized.
Smith said he has been doing an informal study of the bats that roost on campus, in part to give his classes experience and because he is curious about the campus bat population. For one hour once a month, he and his students use a mist net at the same location to catch the bats as they fly out of the roof tiles. They count the number caught, determine the sex and weight of the bats and measure the length of their forearm, which he said is sometimes useful for distinguishing species and sub-species. After the measurements are taken the bats are released. At this point, he said, he's just collecting preliminary data that may lead to other research. He does believe that at least a portion of the campus bats are year-round residents and do not migrate to Mexico for the winter as the Austin bats do.
Meanwhile, Castillo is working on the relocation project for the bats living under the Student Union Building roof tiles. He said the bats are attracted by the smell of rough red cedar, so that's the material that was used to construct eight bat houses, which have been placed in the oak trees in the SUB courtyard. Each house is about 20 inches by 16 inches and 34 inches high, and is open at the bottom. Inside, vertical boards are placed ½-inch apart. The other thing used to attract the bats to their new home is one source of the odor that humans find so offensive - their feces. Smith said, however, that skin glands on the bats are the main source of the musky odor in the SUB.
The first houses were put up just before Thanksgiving and Castillo has seen evidence that the bats are beginning to occupy them.
Castillo had help from Smith and from Texas Parks and Wildlife in developing his bat relocation plan.
The next phase, he said, is the cleanup of the bat guano and sealing of cracks that gave the bats access in the first place. The project will continue through the summer and will be synchronized with SUB renovation. The need for additional bat houses in other parts of campus will be assessed once this project is complete, he said.
Additional information on bats and constructing bat houses can be found at the Bat Conservation International web site at A HREF="http://www.batcon.org.">www.batcon.org
-TAMUK-
- Mary Sherwood