Bats of the Apostles

Big brown bat

Rendered by artist Jan MacFarlane

Background

Apostle Island National Lakeshore (APIS) hosts up to seven bat species: big brown bat (Eptesicus fuscus), eastern red bat (Lasiurus borealis), hoary bat (Lasiurus cinereus), silver-haired bat (Lasionycteris noctivagans), little brown bat (Myotis lucifugus), northern long-eared bat (Myotis septentrionalis), and tricolored bat (Perimyotis subflacus). Big brown bat, little brown bat, and tricolored bat are each listed as threatened in the state of Wisconsin, while northern long-eared bat is listed as both state and federally threatened.

The only true-flying mammals, bats accomplish flight through elongated hands and patagia (bat wings). There are over 1,000 bat species worldwide. Like other mammals, bats produce milk to feed their young, which are called ‘pups’. Females typically birth one pup per year. Many bats have good eyesight, but most species use echolocation to ‘see’ using their ears at night.

Little brown bat

Rendered by artist Jan MacFarlane

Bats benefit their ecosystems as well as the agricultural industry via pest management. Earning their keep, bats provide billions of dollars in economic value per year mostly through pest consumption. All bats found in the park are insectivores, meaning insect-eaters; little brown bats eat up 1000 mosquitoes per night! The eastern red bat, hoary bat, and silver-haired bat are migratory, while the big brown bat, little brown bat, northern long-eared bat, and tricolored bat are hibernators. No bats are known to overwinter in the park.

Little brown bat affected by WNS

NPS photo

White-nose Syndrome

White-nose syndrome (WNS) is a fungal disease that causes spores to grow on the skin of cave-dwelling hibernating bats. WNS causes bats to awaken prematurely from hibernation, deplete their energy reserves, and succumb to starvation before spring arrives. Since the disease’s introduction to the United States in 2006, over one million little brown bats have died of WNS. The disease is known to have a 75-98% mortality rate. Other threats to local bats include climate change, increased wind, and habitat loss.

Did you know? White-nose syndrome does not affect humans! ...and that less than 1% of bats carry rabies.

Ultrasonic recorder on North Twin Island

NPS photo

Bat Research in the Park:

Beginning in 2015, the National Park Service (NPS) Biological Research Division began an ongoing bat monitoring survey in four NPS parks within the Great Lakes Inventory and Monitoring Network (GLKN), including Apostle Islands. In 2016, five additional parks joined the program, with all research being coordinated out of the GLKN office in Ashland, WI.

The project goal is to understand which bat species are present and their relative abundance, as well as to track changes in which calls are heard at a given location. As of 2017, the area surrounding Apostle Islands has been known to have white-nose syndrome present. The data collected through the GLKN project will be used to understand how local bat populations respond to white-nose syndrome and to help develop management plans.

Map of survey sites

Created by Goodwin, K. R., and A. A. Kirschbaum

Within the park, there are 26 sampling sites for acoustic bat data. Each site is visited twice per summer; once to deploy an acoustic monitor, and a second time to retrieve the monitor and data.



For more information: Roxanne Korpela at [e-mail]