Geographically Distributed
Acoustical Monitoring of
Migrating Birds
Harold Mills
Bioacoustics Research Program
Cornell Lab of Ornithology
A Few Birds
Black-and-white Warbler:
Common Yellowthroat:
White-throated Sparrow:
The Birds
•
•
•
•
•
Summer north
Winter south
Migrate spring and fall
Many species migrate at night
Stopover habitat important
Migration Monitoring Methods
• Radar
• Visual
• Acoustical
Acoustical Monitoring
• Provides species identities
• Automatable
• Often more effective than visual
– yields higher counts
– works in the dark
Long-term Goal
• Simultaneous radar and acoustical
monitoring of bird migrations on an
intercontinental scale
• Hundreds of geographically distributed
monitoring stations
• Data collection over the internet
BirdCast
• Simultaneous radar, visual, and acoustical
monitoring of bird migration through the
Delaware river valley and Ithaca, NY
• Spring and Fall 2000
• 9 monitoring stations
• Data collection over the internet
• 27000 warbler and sparrow calls in fall
Monitoring Architecture
Microphone
Transient Detector
Monitoring
Station 1
Transient Detector
Personal
Computer
...
Hard Disk
Uploader
Microphone
Uploader
Internet
Browser (Server)
Database
Personal
Computer
Hard Disk
Browser (Client)
Receiver
Monitoring
Station N
Data
Repository
Browser (Client)
Microphone
•
•
•
•
Custom designed and fabricated
Includes amplifier/filter
Remotely powered for ease of maintenance
Well-protected against water and
mechanical damage
• About $150 for parts
Microphone
Front
Back
Detection Algorithm
Source
Audio
Samples
Input
Parameters
samples
Make
Spectrogram
Spectrogram
Parameters
Estimate Inband
Measure Total
Noise Power,
Compare to
spectra Inband Power powers
bits
Total Inband Power
Detection
Frequency
Band
Noise Power
Estimation Parameters,
Detection Threshold
Identify
Transients
transients
Minimum Event
Separation,
Min/Max Transient
Duration
The transient detector locates concentrations of energy in a
specified frequency band with durations in a specified range.
It saves located transients in AIFF or WAV audio files.
Uploader/Receiver
• Allow detected transients to be uploaded
from monitoring stations to central database
• Use Java Remote Method Invocation (RMI)
for communication over the Internet
• Receiver enters each uploaded transient into
database and makes JPEG spectrograms for
use by browser
Browser
• Allows all users to view and hear transients
stored in database
• Allows selected users to classify transients
• Uses Java RMI for communication over the
Internet
Browser
Results
The Future: More Automation
• Mass-producible microphones
• Automatic classification
• “Live” monitoring stations that upload
transients as they are detected
Acknowledgements
• Programming:
– Christina Ahrens
– Jason Adaska
– Jason Rohrer
• Database and Web Site:
– BirdSource
• Classification:
– Chris Tessaglia-Hymes
• Station Operation:
–
–
–
–
–
–
–
Edward Burton
Don Dunsmore
Laurie Goodrich
Charles Hetzel
Steve Kelling
David Mizrahi
Kenneth Rosenberg