Small Mammals Research: Development of Guidelines to Prevent Excessive Mortality to Bats

Objectives of this research:

• Determine the direction bats migrate from the mine and define spatial and temporal habitat use by bat populations during peak times of spring migration,
• Dtermine habitat use of bats when foraging after emergence from the mine and before spring migration, and
• Propose guidelines for the placement and operation of wind turbines along the Niagara Escarpment to minimize potential negative interaction between bats and turbines.

Background

Wind turbines are being considered to generate commercial electric energy along the north-south oriented portion of Niagara escarpment in eastern Wisconsin. An abandoned iron mine at the southern end of the escarpment, in the town of Neda, Dodge County, is the largest known bat hibernaculum, in the Midwest. Even though many parts of the mine were inaccessible for censusing, the population was estimated to include at least 300,000 bats. Osborn, et al.(1996) list published accounts of bat mortality from collisions with television towers, lighthouses, and wind turbines. They report fatal bat collisions with wind turbines at the Buffalo Ridge Wind Resource Area in southwestern Minnesota. Because of the increasing development of wind energy and documented mortality on bats, there is increasing concern for bats, especially those that occur in high densities. More information is needed on exactly when these bats migrate and what migratory corridors they use when migrating to and from the mine. With this information, wind turbines could be sited in areas that will cause little harm to this significant bat population. With this approach, a "win-win" outcome is likely and wind turbines and bat populations could coexist.

The most important benefit is finding ways to decrease chances of excessive mortality to the largest concentration of bats in the Midwest from wind energy development. Data will be collected to understand bat ecology and migration well enough to permit development of guidelines to achieve that objective. Another important benefit will be to provide a baseline of data to evaluate the potential impact on the mine's bat population once development of wind energy begins in this area. Information from this study will not only be important for the Neda Mine bat population but the information should be useful for siting wind generators elsewhere in the country where abandoned mines have become bat refugia. In addition, this study will advance our knowledge of bat ecology and management that may be useful in addressing other human bat conflicts such as quarrying, rural home development, and highways.

For more information on this topic, please contact:
Steve Ugoretz
(608)-266-6673 or,
Gerald Bartelt
(608) 221-6344