Occurrences

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.

Habitat

Northern long-eared bats live in areas dominated by deciduous or mixed hardwood-coniferous forest. Forests with low understory cover appear to be preferred by this species. In Michigan, northern long-eared bats are associated with karst topography where they utilize small caves and crevices in limestone cliffs as hibernacula. After emerging from hibernation, northern long-eared bats will readily roost in trees, tree hollows, or bark crevices. During the summer, northern long-eared bats are not tied to a specific natural community type and will inhabit any forest with large trees that offer bark that is loose or has deep enough crevices to roost in. Northern long-eared bats do not appear to show preference for dead trees (as some bat species do) and readily roost in living trees. This species rarely roosts in human-made structures.

Natural Community Types

• Dry northern forest
• Dry-mesic northern forest
• Limestone cliff
• Mesic northern forest

Methodology

Management Recommendations

A primary limiting factor in their summer range has been the deforestation of mature forested habitats and the elimination of roost trees, which can be attributed to the cutting of large, dead trees for firewood. Forested habitat can be maintained by protecting mature, wooded areas, leaving large, dead trees standing, and maintaining wide vegetation buffer strips. Cutting of snags, canopy removal, and general land clearing activities for development, agriculture, and utility corridors should be avoided. All stone quarry activity around limestone cliffs pose a threat to this species and should be avoided.

White-nose syndrome has had a staggering impact on northern long-eared bat populations. As a result, this species was listed as threatened under the Endangered Species Act in April, 2015.

Active Period

Breeding from second week of September to second week of October

Migration from second week of August to second week of September

Parturition from second week of June to second week of July

Survey Methods

Mist nets should be set perpendicular to travel corridors such as streams, rivers, and logging trails. A typical net setup is 7 to 9 meters (23-30 ft) high and up to 20 meters (66 ft) wide. Surveys should consist of a minimum of 1 net site per kilometer of habitat corridor and 2 sites per square kilometer of habitat. Mist netting at a site should be conducted for four nights and in at least two different locations within a site. Nets should be checked every 20 minutes from sunset to sunrise. The species is most active 25 minutes after sundown to 4 hours after sundown. Due to the continued spread of white-nose syndrome any mist netting for bats must take precautions to disinfect equipment being used.

Mist netting

Survey Period: From first week of June to fourth week of July

Time of Day: Night

References

Survey References

• Kurta, A. 2008. Bats of Michigan. Indiana State University Center for North American Bat Research and Conservation, Terre Haute, Indiana, 72 pp.

• U.S. Fish and Wildlife Service. 2018. Range-Wide India Bat Survey Guidelines.

• Wisconsin Department of Natural Resources. 2013. Wisconsin Little Brown Bat Species Guidance. Bureau of Natural Heritage Conservation, Wisconsin Department of Natural Resources, Madison, Wisconsin. PUB-ER-705