Endangered Bat Surveys


Bat Services

The United States Fish and Wildlife Service (USFWS) protects critically imperiled species from extinction by regulating harm (or “Take”) of listed animals and their habitat through the regulations set forth in the Endangered Species Act of 1973 (ESA). Additionally state wildlife resource agencies further regulate the harm of species that occur in low numbers within the state borders. As protection for listed species the USFWS has established a coordination and permitting structure that project proponents need to comply with to ensure that no harm is done to an already imperiled species. EnviroScience biologists are highly familiar with the coordination process and the surveys that may be required as a result. We have experience with projects of all types and sizes across the range of listed U.S. endangered bats. Our clients include federal, state and local government agencies, coal, energy and industry companies, transportation departments, developers, and private companies. EnviroScience endangered bat survey capabilities include:

  • Full coordination with USFWS and state regulatory agencies
  • Records Search and Desktop Review
  • Habitat, Tree, and Potential Hibernacula Surveys
  • Emergence Surveys
  • Mist-net Surveys
  • Acoustical Monitoring
  • Radio Telemetry
  • Habitat Conservation Plans
  • Biological Assessments

EnviroScience highly recommends initiating the coordination process with both the USFWS and state agencies as soon as possible in the project planning process to avoid delays or other restrictions to project completion. Listed endangered bats for which coordination may be necessary include the Indiana bat, Northern Long-eared bat, Virginia Big-eared bat, and the Gray bat, as detailed below. EnviroScience can assist with coordination and surveys for these and any other bat as needed.


Indiana Bat Range

Indiana Bat Range (Source: Wikimedia Commons)

The Indiana bat (Myotis sodalis) is a medium-sized bat which was listed as a federally endangered species by the United States Fish and Wildlife Service (USFWS) in 1967. As a listed species activities that may have an effect on the species are regulated by the USFWS. The Indiana bat is considered a cave dwelling bat, in that it hibernates in caves during cold winter months. In the warmer spring and summer months the Indiana Bat uses forested habitats across its range to roost, forage, and rear young. Because of their summer use of forested habitats, projects that involve clearing or removal of trees or other potential habitats must go through coordination with the USFWS.


Virginia Big-Eared

Virginia Big-Eared (Source: USFWS)

The Virginia Big-eared bat (Corynorhinus townsendii virginianus; VBEB) is a medium-sized bat with long ears and distinct facial glands around its snout. The VBEB was listed as a federally endangered species by the USFWS in 1979. It occurs in a very small range including select counties in Kentucky, North Carolina, Virginia, and West Virginia. The VBEB lives in caves, usually associated with oak-hickory or beech-maple-hemlock forested areas, in both the winter and summer. As a listed species activities that may have an effect on the species or their habitat are regulated by the USFWS and state agencies.

Ozark Big-eared Bat Range

Ozark Big-eared Bat Range (Source: USFWS)

The Ozark Big-eared bat (Corynorhinus townsendii ingens; OBEB) is another medium-sized bat with long ears and distinct facial glands around its snout. The OBEB was listed as a federally endangered species by the USFWS in 1979. It is endemic to the Ozark Highlands and Boston Mountains in Arkansas, Missouri, and Oklahoma. The OBEB lives in limestone and sandstone talus caves year round, usually associated with oak-hickory hardwood forested areas. As a listed species activities that may have an effect on the species or their habitat are regulated by the USFWS and state agencies.


Northern Long-Eared

Northern Long-Earned Bat Range (Source: Bob Rinela at Specialized Ecological Services)

The Northern Long-eared bat (Myotis septentrionalis; NLEB) is a medium-sized bat that closely resembles the Indiana bat in physical and behavioral characteristics, but has long ears that extend past the snout when pashed forward. The NLEB is also a cave dwelling bat that hibernates in caves during the winter months, then roosts and rears young in forests across its range in the spring and summer. In response to a disease called White Nose Syndrome (WNS), which is a fungus that depletes the energy reserves of hibernating bats and causes mortality upon arousal from hibernation, the USFWS listed the NLEB as federally threatened with an interim 4(d) rule on May 4, 2015. 

UPDATE: On March 22, 2022, the USFWS announced a proposal to reclassify the northern long-eared bat (Myotis septentrionalis; NLEB) from “threatened” to “endangered” under the ESA. The change is a direct result of a January 28, 2020 ruling by a federal judge in favor of a lawsuit, Center for Biological Diversity v. Everson, that USFWS’s 2015 threatened listing of the NLEB did not adequately protect the species under the ESA. After a review of the best available scientific and commercial information, USFWS found that the NLEB meets the ESA’s definition of an endangered species and proposed uplisting its status accordingly.

The proposed rule to uplist the NLEB from threatened to endangered was posted on the Federal Register on March 23, 2022, and public comments may be submitted through May 23, 2022. A final decision is expected in November 2022.

Transportation projects covered under various programmatic consultations will not be impacted by the reclassification provided they are completed by the end of the year. Biologists strongly encourage mist-net surveys proposed for the 2022 summer survey season to include radiotelemetry on NLEB. EnviroScience bat biologists routinely conduct both acoustic and mist-net bat surveys, develop conservation and management plans, and work with clients to create conservation and avoidance measures. Our team is qualified and able to help you navigate your project through the ESA Section 7 Consultation process. We are keeping up with the latest information and are available at 800.940.4025 to answer any questions or concerns as to what this proposed reclassification may mean for your projects.


Gray Bat Range

Gray Bat Range (Source: Wikimedia Commons)

The Gray bat (Myotis grisescens) is another medium-sized bat of the Myotis genus which was listed as a federally endangered species by the USFWS in 1976. Similar to the Indiana and Northern Long-eared bats, but larger and with a uniform gray pelage. The Gray bat occupies caves year round, cold caves in the winter and warm caves in the summer. Foraging is usually associated with rivers, streams, lakes, or reservoirs. As a listed species activities that may have an effect on the species are regulated by the USFWS.



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    Map Credits:

    Indiana Map from Wikimedia Commons

    Northern Long-eared Bat Map by Bob Rinela at Specialized Ecological Services

    Gray Bat Map from Wikimedia Commons

    Virginia Big-eared Map from  USFWS

    Ozark Big-eared Map from USFWS