Wisconsin Bat Facts

Wisconsin bats belong to suborder Microchiroptera, the smaller bats.  Depending on the species, the bats either roost in trees or caves.  Tree-roosters migrate seasonally and live under the bark of trees while they summer in the Midwest.  Cave bats hibernate over the winter.  They roost in caves, or similar environments, like ledges, attics, or specially constructed bat boxes.  Both types of bat feed on moths and insects.

Bats are responsible for pollinating and seed dispersal of many plants.  They are insect control agents and contribute to cave ecosystems.  Threats to bat population include habitat loss, toxins from pesticide use, wind turbines and, perhaps most critical, white nose syndrome.  Bats contract white nose syndrome during hibernation in caves.  It is caused by a Eurasian fungus, most likely brought to North America by cave tourists.  They carry the fungus on their equipment and subsequently contaminate the caves they explore.

Bat Lifecycle

April – May: Migration

June – July: Birthing and rearing (bats usually produce one offspring per year)

August – September: Mating and pre-migration/hibernation

Common Wisconsin Species

• Little brown bat (Myotis lucifugus): High-frequency call (> 35 kHz); Hibernates in caves and mines; Females form maternity colonies
• Northern longeared bat (Myotis septentrionalis): Hibernates in caves; Roosts in trees during the summer;
• Big brown bat (Eptesicus fuscus): Has a low-frequency call (< 35 kHz); cave-roosting bat
• Hoary bat (Lasiurus cinereus): White-tipped fur; largest bat in Wisconsin with a wingspan of 13-16 inches

Explore the following links for more information on bats and bat monitoring activities in Wisconsin:

Bat Conservation of Wisconsin http://www.batcow.org/ 

Wisconsin Bat Monitoring Program http://wiatri.net/inventory/bats/Monitoring/index.cfm