Massachusetts Department of Transportation Bat Monitoring - Environmental Services On-Call Contract


For decades, VHB has partnered with the Massachusetts Department of Transportation (MassDOT) by providing environmental, engineering, and planning services. VHB’s environmental team delivers wide-ranging ecological services including threatened and endangered species studies and acoustic bat monitoring. These services support MassDOT in securing permits to maintain and enhance the Commonwealth’s transportation infrastructure.

When the Nothern Long-eared Bat (NLEB) became federally threatened in 2015, MassDOT became proactive about documenting the presence or probable absence of NLEB to determine if ESA consultation and mitigative strategies for NLEB would need to be incorporated into project schedules. VHB has been supporting MassDOT with this risk-management approach since 2015 by performing due diligence acoustic bat surveys and visual bridge assessments throughout the state each survey season.

Each year, VHB biologists evaluate the survey effort of priority MassDOT projects throughout the state in accordance with the most recent U.S. Fish and Wildlife Service (USFWS) survey guidelines and develop a study plan to be reviewed and approved by USFWS prior to initiating the surveys. Upon approval of the study plan, VHB biologists conduct the surveys using Pettersson D500x full spectrum ultrasound acoustic detectors and site them in the field to optimize the cone of detection and target potential flyways for commuting bats.

VHB biologists trained in conducting acoustic analyses perform automated call analysis and the qualitative review (manual vetting) of call files. Full spectrum files are auto classified with Kaleidoscope Pro and qualitative analysis of high frequency calls is conducted using SonoBat. VHB biologists complete four reporting deliverables for each survey effort: a survey report that addresses all criteria established by USFWS; the USFWS Northeastern US Bat Reporting Spreadsheet; spatial data providing the survey location and survey results of each survey location; and metadata and call files are prepared in accordance with NABat specifications and uploaded to their website to contribute to the North American bat survey database.

During the 2022 survey season, VHB conducted 180 detector nights of acoustic surveys and 19 visual bridge assessments. VHB is currently working with MassDOT and USFWS to conduct Section 7 consultation where NLEB presence has been confirmed via acoustic monitoring. VHB was also a co-panelist with MassDOT biologists at the 2023 Northeast Bat Working Group Conference in Burlington, VT to discuss strategies and challenges of conducting bat surveys while maintaining project schedules.

Bridge base documented during visual assessment


  • Massachusetts Department of Transportation


  • Environmental Assessment

  • Habitat Assessment

  • Restoration & Monitoring

  • Threatened & Endangered Species Surveys