Reclassification of the Northern Long-eared Bat

How VHB can support clients navigating the endangered status of NLEB.

The northern long-eared bat (Myotis septentrionalis; NLEB) has been reclassified from threatened to endangered by the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Act (ESA; 16 U.S.C. § 1531 et seq.). Listed as threatened in 2015, the NLEB is endangered with extinction largely due to white nose syndrome, a disease caused by an introduced fungal pathogen that has decimated the NLEB population. NLEB is a far-ranging species occurring across 37 states in a variety of habitat types and projects across this footprint must consider impacts to this newly endangered species.

The final rule classifying the NLEB as endangered went into effect on March 31, 2023. Preceding the effective date of the ruling, the USFWS released new tools and resources to aid stakeholders in assessing project impacts to NLEB. VHB biologists have closely followed the regulatory changes and guidance documents surrounding the new ruling so we can best support clients navigating this change at every stage of their projects.

Range of the northern long-eared bat in relation to VHB locations.
Range of the northern long-eared bat in relation to VHB locations.

How can VHB help

VHB has specialized in bat survey and analysis services since the NLEB became federally threatened under the ESA in 2015. Since that time, VHB has trained biologists to specialize in bat survey techniques including acoustic, mist netting, emergence, and visual assessment surveys. Biologists are trained in bat call analysis using auto-classification software and qualitative analysis of calls in full-spectrum and zero-cross format. VHB works closely with clients and regulators to convey survey results, facilitate Section 7 consultations under the ESA, and determine whether and what conservation measures are required to provide protection to NLEB while working to achieve project goals and schedules. We understand that addressing sensitive resource issues early, like a project’s potential impacts on rare, threatened, and endangered (RTE) species, are a critical regulatory hurdle required to move a project from concept to completion.

Survey Techniques

checklist-icon.pngWith NLEB populations in decline and federal and state protections expected to increase for other bat species, clients are turning to VHB to conduct bat surveys to support project consultations under Section 7 of the ESA. VHB specializes in performing presence/probable absence (P/A) surveys targeting the NLEB and other priority bat species that are being considered for protection under the ESA, including the tri-colored bat (Perimyotis subflavus) and the little brown bat (Myotis lucifugus).

Habitat Assessments

Home-Icon.pngOne of the primary steps to evaluating the potential impacts of a proposed action on NLEB is the initial determination of the presence of suitable habitat within the project’s action area. VHB biologists are well-versed in the assessment of suitable NLEB habitat and understand that the occurrence of NLEB across its known range been refined by USFWS via survey data and spatial occupancy modeling. VHB biologists will recommend if a follow-up P/A survey is needed based on the new consultation tools released by USFWS, the presence of suitable NLEB habitat, and the potential impacts of the proposed project on NLEB.

Acoustic Surveys

Noise-Icon.pngAcoustic surveys are a key means to conducting P/A surveys to determine whether a project must incorporate NLEB conservation measures. VHB’s biologists are proficient in acoustic data management, metadata compilation, scrubbing of non-bat call data, and the application of auto-classification software approved by USFWS to conduct preliminary classification of low- and high- frequency bat calls to species. VHB’s biologists also qualitatively review spectrograms of high frequency bat calls to identify the calls to species. This skill is essential in evaluating the presence of federally- or state-listed bats in a project area since auto-classification software can be unreliable in differentiating between high-frequency species such as NLEB, other Myotis species, and tricolored bat.

Visual Assessments

Magnifying-Glass-Icon.pngVHB biologists conduct visual assessments in bridge and culvert structures to identify indicators of roosting bats through auditory and visual cues such as staining and guano. If positive indicators for roosting are present, VHB works with clients to identify the next steps, which could include guano sampling for DNA analysis to identify species present, acoustic or emergence surveys, or coordination with the local state or federal agency to assume presence and implement avoidance and minimization measures (AMMs) or other conservation measures. The VHB team also partners with clients to establish appropriate traffic controls and other means of access as necessary.


Hand-Icon.pngVHB holds a Section 10 Species Recovery Permit issued by the USFWS which allows for survey methods that require the handling of specific federally listed bat species. VHB biologists are experienced in conducting mist netting surveys which allow for the identification of bats-in-hand. This is another P/A survey technique and is sometimes used as a follow-up to acoustic surveys and is important in states where the range of certain Myotis species overlap because their calls can be difficult to distinguish with acoustic surveys alone.


Meeting-Icon.pngVHB works closely with clients and regulators to deliver survey results, facilitate Section 7 consultations under the ESA, and determine whether conservation measures are required to provide protection to NLEB while working to achieve project goals and schedules. VHB is prepared to assist clients with the newly issued consultation framework for NLEB and is proficient in the standard consultation framework for other federally protected species. VHB biologists are also prepared to assist clients outside of the federal nexus stay in compliance with Section 9 of the ESA, which prohibits take of federally listed species.

Data Management

Wave-Icon.pngVHB has collected and managed bat call data since 2015. Upon client request, VHB will prepare call files and metadata for upload to the North American Bat Monitoring Program (NABat), a collaborative network that collects monitoring data across the continent to improve the science of where, when, and how bat populations are changing over time. Sharing data through NABat has the double benefit of increasing the data inventory of bat surveys while also providing a secondary storage location for bat call files.