Eco-acoustics

Monitoring biodiversity through sound

Current status of this initiative

This page is currently a place holder for some more concrete plans to establish an automated or semi-automated eco-acoustic monitoring network in key parts of Oberon SLA. More details to follow in due course.

Inspired by the capabilities of the Birdweather PUC and BirdNET-pi bird call monitoring stations, which are small computing devices which use machine learning (a limited form of artificial intelligence) to automatically detect and classify bird calls from audio they automatically record from attached microphones, OCSN plans to investigate the more general utility of eco-acoustics for ecological and biodiversity surveys in the Oberon region.

The AudioMoth low-power digital recording device, with battery holder for three AA cells for scale

One of the problems with the Birdweather PUC and BirdNet-pi devices is that they require quite a lot of power to run (relatively speaking, in fact they use only a few watts, about as much as a small LED light bulb, which is very little when mains power is available, but quite a lot if it has to be supplied by batteries for any length of time). This makes them more suited to deployment near buildings which can supply 5 volt power to them continuously from a small mains-powered power supply unit (or via power-over-ethernet if they are connected via a network cable). The relatively high power requirement is due to the fact that the devices are doing edge computing, that is they are continuously evaluating (running) the machine learning models they use, and this requires quite a lot of computing power and hence electrical power.

The weatherproof case for the AudioMoth device, which can be strapped to a tree branch or similar.

AudioMoth

For longer-term deployment in more remote locations, such as in forests and conservation areas, a different strategy is required. For this reason, OCSN plans to evaluate the AudioMoth, a low-power device developed at Cambridge University in the UK, designed to be battery-powered and to allow digital audio recordings of the environment to be captured continuously for one or more weeks at a time. Weatherproof cases for these devices are also available.

There is even a version for underwater recording – possibly to capture the sounds made by platypuses?

The strategy for using them would be to position them at key locations to be monitored, leave them there for one or two weeks, then collect them and download the recorded sound files for off-line processing on laptop or desktop computers, or using cloud computing. The audio files can even be made freely available on the internet to allow others to assist in the computerised processing of them to extract information about bird, frog and other animal calls from them. After collection, the batteries would be recharged and the device repositioned at the next target location.

The totally watertight case for the HydroMoth device

Titley Scientific

Titley Scientific is an Australian company based in Brisbane which designs and manufactures a range of ecoacoustic monitoring devices, including automated bat detectors and high-end audio recorders capable of recording both audible calls from birds and frog, but also ultrasounic sound emitted by bats. The devices are not cheap, but they are very well-regarded by ecologists and are fully supported locally, complete with easy-to-use software to enable screening of recordings. They also have a loan program for citizen science groups! OCSN plans to acquire at least one of their devices as soon as possible to assess their utility. For more information, see the Titley Scientific web site.

A Titley Scientific Scout recorder attached to a tree, capable of simultaneously recording both audible and ultrasonic sound for weeks at a time, for later analysis.

Titley are putting on a series of three 30 minute seminars between August and October 2024 on recording ultrasound. Links to unlisted recordings of these mini-seminars appear below (please do not share or republish the links). Note that the first one ends abruptly because they reached the limit of their free seminar hosting on Zoom, something they fixed for the second seminar.

Other resources