Northern Long-Eared Bat

Myotis septentrionalis

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The northern long-eared bat is federally listed as a threatened species under the Endangered Species Act.  Endangered species are animals and plants that are in danger of becoming extinct. Threatened species are animals and plants that are likely to become endangered in the foreseeable future. Identifying, protecting, and restoring endangered and threatened species is the primary objective of the U.S. Fish and Wildlife Service’s endangered species program.

 

What is the northern long-eared bat?

Appearance: The northern long-eared bat is a medium-sized bat with a body length of 3 to 3.7 inches but a wingspan of 9 to 10 inches.  Their fur color can be medium to dark brown on the back and tawny to pale-brown on the underside.  As its name suggests, this bat is distinguished by its long ears, particularly as compared to other bats in its genus, Myotis.

 

Winter Habitat: Northern long-eared bats spend winter hibernating in caves and mines, called hibernacula.  They use areas in various sized caves or mines with constant temperatures, high humidity, and no air currents.  Within hibernacula, surveyors find them hibernating most often in small crevices or cracks, often with only the nose and ears visible.

 

Summer Habitat: During the summer, northern long-eared bats roost singly or in colonies underneath bark, in cavities or in crevices of both live trees and snags (dead trees).  Males and non-reproductive females may also roost in cooler places, like caves and mines.  Northern long-eared bats seem to be flexible in selecting roosts, choosing roost trees based on suitability to retain bark or provide cavities or crevices.  This bat has also been found rarely roosting in structures, like barns and sheds. 

 

Reproduction: Breeding begins in late summer or early fall when males begin to swarm near hibernacula.  After copulation, females store sperm during hibernation until spring.  In spring, they emerge from their hibernacula, ovulate and the stored sperm fertilizes an egg.  This strategy is called delayed fertilization.

 

After fertilization, pregnant females migrate to summer areas where they roost in small colonies and give birth to a single pup.  Maternity colonies of females and young generally have 30 to 60 bats at the beginning of the summer, although larger maternity colonies have also been seen.  Numbers of individuals in roosts, typically decreases from pregnancy to post-lactation.  Most bats within a maternity colony give birth around the same time, which may occur from late May or early June to late July, depending where the colony is located within the species’ range.  Young bats start flying by 18 to 21 days after birth.  Maximum lifespan for the northern long-eared bat is estimated to be up to  to 18.5 years. 

 

Feeding Habits: Like most bats, northern long-eared bats emerge at dusk to feed.  They primarily fly through the understory of forested areas feeding on moths, flies, leafhoppers, caddisflies, and beetles, which they catch while in flight using echolocation or by gleaning motionless insects from vegetation. 

 

Range: The northern long-eared bat’s range includes much of the eastern and north central United States, and all Canadian provinces from the Atlantic Ocean west to the southern Yukon Territory and eastern British Columbia. The species’ range includes the following 37 States and the District of Columbia: Alabama, Arkansas, Connecticut, Delaware, Georgia, Illinois, Indiana, Iowa,  Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, West Virginia, Wisconsin, and Wyoming. 

 

Why is the northern long-eared bat in trouble?

White-nose Syndrome: No other threat is as severe and immediate as the disease, white-nose syndrome.  If this disease had not emerged, it is unlikely the northern long-eared bat would be experiencing such a dramatic population decline.  Since symptoms were first observed in New York in 2006, white-nose syndrome has spread rapidly from the Northeast to the Midwest and Southeast; an area that includes the core of the northern long-eared bat’s range where it was most common before this disease.  Numbers of northern long-eared bats (from hibernacula counts) have declined by up to 99 percent in the Northeast.  Although there is uncertainty about the rate that white-nose syndrome will spread throughout the species’ range, it is expected to spread throughout the United States in the foreseeable future.

 

Other Sources of Mortality: Although no significant population declines have been observed due to the sources of mortality listed below, they may now be important factors affecting this bat’s viability until we find ways to address white-nose syndrome.

 

Impacts to Hibernacula:  Gates or other structures intended to exclude people from caves and mines not only restrict bat flight and movement, but also change airflow and internal cave and mine microclimates.  A change of even a few degrees can make a cave unsuitable for hibernating bats.  Also, cave-dwelling bats are vulnerable to human disturbance while hibernating.  Arousal during hibernation causes bats to use up their already reduced energy stores, which may lead to individuals not surviving the winter.

 

Loss or Degradation of Summer Habitat:Loss or Degradation of Summer Habitat:  Highway construction, commercial development, surface mining, and wind facility construction permanently remove habitat and are activities prevalent in many areas of this bat’s range.  Forest management benefits northern long-eared bats by keeping areas forested rather than converted to other uses.  But, depending on type and timing, forest management activities can cause mortality and temporarily remove or degrade roosting and foraging habitat.

 

Wind Farm Operation: Wind turbines kill bats, and, depending on the species, in very large numbers.  Mortality has been documented for northern long-eared bats, although a small number have been found to date.  However, there are many wind projects within a large portion of the bat’s range and many more are planned.

 

What Is Being Done to Help the Northern Long-Eared Bat?

Disease Management: Actions have been taken to try to reduce or slow the spread of white-nose syndrome through human transmission of the fungus into caves (e.g. cave and mine closures and advisories; national decontamination protocols).  A national plan was prepared by the Service and other state and federal agencies that details actions needed to investigate and manage white-nose syndrome.  Many state and federal agencies, universities and non-governmental organizations are researching this disease to try to control its spread and address its affect.  See www.whitenosesyndrome.org/ for more.

 

Addressing Wind Turbine Mortality: The Service and others are working to minimize bat mortality from wind turbines on several fronts.  We fund and conduct research to determine why bats are susceptible to turbines, how to operate turbines to minimize mortality and where important bird and bat migration routes are located.  The Service, State natural resource agencies, and wind energy industry are developing a Midwest Wind Energy Habitat Conservation Plan that will provide wind farms a mechanism to continue operating legally while minimizing and mitigating listed bat mortality.

 

Listing: The northern long-eared bat is listed as a threatened species under the federal Endangered Species Act.  Listing a species affords it the protections of the Act and also increases the priority of the species for funds, grants, and recovery opportunities.

 

Hibernacula Protection: Many federal and state natural resource agencies and conservation organizations have protected caves and mines that are important hibernacula for cave-dwelling bats.

 

What Can I Do to Help the Northern Long-Eared Bat?

Do Not Disturb Hibernating Bats: To protect bats and their habitats, comply with all cave and mine closures, advisories, and regulations.  In areas without a cave and mine closure policy, follow approved decontamination protocols (see http://whitenosesyndrome.org/topics/decontamination) - under no circumstances should clothing, footwear, or equipment that was used in a White-nose Syndrome affected state or region be used in unaffected states or regions.

 

Leave Dead and Dying Trees Standing: Like most eastern bats, the northern long-eared bat roosts in trees during summer.  Where possible and not a safety hazard, leave dead or dying trees on your property.  Northern long-eared bats and many other animals use these trees.

 

Install a Bat Box: Dead and dying trees are usually not left standing, so trees suitable for roosting may be in short supply and bat boxes may provide additional roost sites.  Bat boxes are especially needed from April to August when females look for safe and quiet places to give birth and raise their pups.

 

Support Sustainability:  Support efforts in your community, county and state to ensure that sustainability is a development goal.  Only through sustainable living will we provide rare and declining species, like the northern long-eared bat, the habitat and resources they need to survive along with us. 

 

Spread the Word:  Understanding the important ecological role that bats play is a key to conserving the northern long-eared and other bats. Helping people learn more about the northern long bat and other endangered species can lead to more effective recovery efforts.  Visit www.whitenosesyndrome.org for more information about white-nose syndrome.

 

Join and Volunteer:  Join a conservation group; many have local chapters. Volunteer at a local nature center, zoo, or national wildlife refuge.  Many state natural resource agencies benefit greatly from citizen involvement in monitoring wildlife.  Check your state agency websites and get involved in citizen science efforts in your area.

 

Updated April 2015

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Last updated: July 19, 2016