Gretchen Meyer and James Reinartz
UWM Field Station, gmeyer@uwm.edu, jimr@uwm.edu
The Neda Mine, an abandoned iron mine located near Iron Ridge in Dodge Co., supports about 150,000 bats each winter, making it among the largest hibernacula in the midwest. The mine is used primarily by little brown bats (Myotis lucifugus), with northern bats (M. septentrionalis), eastern pipistrelles (Perimyotis subflavus), and big brown bats (Eptesicus fuscus) found in smaller numbers. We have been monitoring bat activity at the mine since 2001 using an infra-red photo beam-break detection system that records bats entering and leaving the mine on a 5-minute interval 365 days per year. We have been collecting temperature data since 1996 using battery-powered temperature dataloggers at 10 locations within the mine and 2 locations outside. We are also monitoring airflow in the mine. We are currently using these data to examine trends over time in winter temperatures in the mine, and the phenology of bat emergence in spring. The fungus that causes Whitenose syndrome, a devastating disease that attacks hibernating bats, was detected at Neda Mine in 2015. Our study provides important baseline data on hibernation behavior of healthy bats, and will help us document changes in bat behavior now that the disease has arrived at Neda Mine.