The following was sent to the NMCaver list by Pat Seiser, and since Austin has the famous urban bat colony I thought it would also be of interest to Texas cavers.
Mark Minton Bat populations in Oregon have been in decline for the past several decades, and now, ODOT is in a position to help reverse the trend. Why? Bats often use the narrow spaces between beams under highway bridges and other structures as nesting and roosting habitats. During the day, these shelters protect bats from predators and weather conditions. At night, the structures offer bats a place to rest and digest their food between nocturnal feedings. And in spring, bats give birth to and raise their young in these safe shelters. Now, through the OTIA III State Bridge Delivery Program, ODOT is helping make and keep bridges even more bat-friendly. Currently, only one percent of American highway structures provide ideal day roost conditions, but minor modifications in the design and construction of future structures can easily provide homes for millions of bats. Bats actually prefer concrete an excellent heat conductor as roosting material. However, modern bridge structures use precast concrete that, although more cost-effective and efficient, lacks the texture and crevices bats need to be able to roost safely and comfortably. ODOT biologists, in collaboration with Oregon Department of Fish and Wildlife and U.S. Forest Service biologists, have developed bat habitat performance standards to help bridge engineers plan construction with bat habitats in mind. With maximum forethought and minimal or no increased cost, bridge program contractors are modifying many new designs to remain attractive to bats. Engineers lay grit sandpaper in the plywood forms to create a textured surface in the concrete that bats can more easily grip during night roosting. They space girders to encourage day roosting so the bats can adjust to rising and falling temperatures, and they introduced an innovation called the "Oregon wedge," an inexpensive method of retrofitting bridges or culverts with day-roost habitats. The wedge is made from an exterior-grade plywood panel with wood strips attached along the top and sides, leaving an opening along the bottom. One reason its important to preserve and build bat habitats is the contribution these unique creatures make to controlling the insect populations that "bug" humans yet another way Oregonians benefit from ODOTs work! _______________________________________________ Texascavers mailing list [email protected] http://texascavers.com/mailman/listinfo/texascavers_texascavers.com
