Methods & Technology

Active Monitoring

  • Acoustic surveys at randomly distributed locales
  • Monthly “Bat Blitzes” with the assistance of Citizen Bat Scientists
  • North American Bat Monitoring protocol survey component:
    • Mobile acoustic surveys along road transects
  • Bat house/bat condo installation w/regular monitoring to determine use and species richness

Passive Monitoring

  • North American Bat Monitoring protocol passive (stationary) point survey component:
    • Two or four passive data collectors will be deployed for 4-night periods at various features (e.g., grassland, oak woodland, pond, riparian corridor) across the landscape within predetermined NABat sampling grids. A grid cell sample unit of 10 km by 10 km (100 km²) has been determined as an effective sampling framework in context with NABat’s focal analytical goal for regional and range-wide assessments. The grid was developed by the U.S.D.A. Forest Service for use in the inter-agency “Bat Grid” monitoring program in the Pacific Northwest and has now been expanded across Canada, the United States, and Mexico, and now including California’s Central Coast.
  • Landscape feature benefit analysis modeled after Heim et al (2015): Bats&LandscapeElements 

Hardware

North American Bat (NABat) Monitoring protocols:

For Passive Acoustic Surveys

  • Pettersson D500x full spectrum bat detector/ultrasound recorder
  • Wildlife Acoustics SM3BAT 2-channel full spectrum bat detector/ultrasound recorder
  • Wildlife Acoustics SM4BAT ZC native zero-crossing bat detector/recorder

For Mobile Acoustic Surveys

  • ANABAT Swift full spectrum bat detector/ultrasound recorder w/car mount 

General Bat Monitoring & Distribution Studies:

For Active Monitoring

  • Pettersson M500-384 USB ultrasound microphone paired w/Android device
  • Pettersson D240x heterodyne and full spectrum time expansion bat detector paired with Zoom H-2 digital audio recorder

For in-field teaching, public demonstrations, and active monitoring by citizen scientists and elementary school students

  • Wildlife Acoustics Echo Meter Touch paired with iPhone/iPad

For heterodyne (focused/limited frequency) monitoring & surveys

  • Pettersson D240x heterodyne and full spectrum time expansion bat detector paired with Zoom H-2 digital audio recorder

Loaner units for citizen scientists

  • Wildlife Acoustics Song Meter SM2BAT
  • Wildlife Acoustics Song Meter SM2BAT+
  • Wildlife Acoustics Echo Meter Touch (Android and Apple iOS versions)

Software

  • SonoBat (SonoBat, Inc./Joe Szewczak, Humboldt State University) – for full spectrum analysis
  • Kaleidoscope Pro (Wildlife Acoustics) – for zero-crossed file inspection and full spectrum analysis
  • AnaLookW software for zero-crossed file inspection

Manual vetting

The importance of manual vetting of bat call files cannot be undervalued. For every location, to ascertain presence of a species, we manually vet a sufficient number of files in order to establish at least one peer review-able voucher. We tailor our vetting process to fit the need of our studies, which on occasion may result in the inspection of each bat call file that we have recorded. We consider both false positive and false negatives when interpreting the results from our auto-classifier programs.