Indiana bat

Distribution and Habitat

Indiana bats are found over most of the eastern half of the United Sates, from Michigan, New York, and Connecticut in the north, and southward to Florida and Alabama. Their range stretches westward to Iowa, Missiouri, Arkansas, and Oklahoma. The Indiana bat is among the six NJ bat species that are active throughout the late spring, summer, and early fall but go into dormancy during the cold winter months, hibernating in caves and abandoned mines (three other NJ bat species migrate south for the winter).

The Indiana bat is highly selective of hibernation sites, called hibernacula. It tends to prefer medium-sized caves with large, shallow passageways. Ideal conditions insides caves include an average temperature of 37 to 43 degrees Fahrenheit and a relative humidity of 87%. Indiana bats can hibernate together in clusters of more than 400 bats per square foot. They often hibernate with other species. At the Hibernia Mine in Morris County, New Jersey, Indiana bats hibernate primarily with little brown bats, as well as lower numbers of northern longeared, tri-colored (pipistrelle), big brown, and eastern small-footed bats.

During the summer, female Indiana bats occupy maternity roosts of up to 100 or more females. They tend to roost under the bark of dead and dying trees but have also been found living under the loose bark of living trees such as the shagbark hickory. Roost trees are generally in sunny locations near water, where insects are plentiful and mother bats can replenish the liquids needed for nursing. Males tend to roost alone or in small groups, usually near female roosts. However, some adult males may choose to occupy caves during the summer as well. Roost sites tend to be located far from roads, usually at least 3,000 feet.

In January of 2009, NJ biologists discovered the presence of White-nose Syndrome (WNS) at three of the largest bat hibernacula in the state. WNS is named for the white fungus that appears on the muzzles and other membranes of affected bats, which as a.jpg’esult of the condition often die of starvation and dehydration over winter. Mortality rates are nearly 100% at many sites. As of April 2009, just three winters since its discovery in New York, WNS had spread to nine northeast states and killed an estimated one million bats.

Mortality rates (from the effects of white-nose symdrome) are nearly 100% at many sites.

New Jersey is participating in several research projects that are looking into the causes of WNS, its means of spreading, and possible treatments or solutions. Spring emergence surveys, summer bat counts, bat banding, fur and tissue sampling, and maternity colony monitoring are a few ongoing efforts. CWF is also working with forest landowners in north Jersey to create natural roosts for tree bats like the Indiana bat. Since tree bats prefer to roost under loose or dead bark in sunny locations, these projects include girdling (killing) select trees, clearing other trees around them to increase sunlight, and attaching loose-bark mimicking materials to provide bats with extra, longer-lasting shelter. Hibernia Mine, wintering home to some of NJ’s Indiana bats, was gated in 1994 to protect them.

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