Good morning COG/Canberra Birds members and chat line subscribers, a reminder that our August monthly will be held tomorrow evening Wednesday 12 August from 7:30 pm.
Apart from the reminder that there has been a change in venue
as detailed in bold red below, what readers may not be aware of is that it is currently planned Coppins Crossing will be closed from 2 am on Wednesday (tomorrow) morning
(see
https://www.act.gov.au/builtforcbr/browse-all-projects/transport/molonglo-river-bridge).
This particularly has an impact on northside attendees, though it could possibly still change due to the recent very wet weather, and
so please monitor this and plan your journey accordingly.
Also, unfortunately Jurian Hoogewerf is now unable to deliver his presentation. Instead, he is proposing to record part of his presentation, which Zac can then show. Otherwise, Zac has re-jigged part of
his presentation to cover the bioacoustic aspects.
Also, chairs will need to be set up before the meeting and put away after.
Everyone is welcome so please come along to listen to different presentations about aspects of bird surveys as detailed below.
You will also be able to enjoy a cup of tea or coffee after the meeting.
Jack Holland
Speakers for the 12 August meeting will be:
Zac Flegg -
Canberra Bird Blitz Summary
Jurian Hoogewerff
-
Introduction to technical aspects of ecoacoustic recording
Zac Flegg -
Nightjars in the Cotter - Methods, Findings and Ethical Implications
Change of meeting venue for COG/Canberra Birds
Until further notice the venue for our 2026 monthly members' meetings will remain the Bugang Room at the Denman Village Community Centre, located at 5 Felstead
Vista, adjacent to the Denman Prospect shops (see Google Maps link
https://maps.app.goo.gl/NqW3XrN5iJf8dzRe9)
This is a light, spacious, modern event venue with a kitchen. There is plentiful parking, under lights, close to the door and with several disabled parking spots outside the
door. The room is on the first floor, accessed by two flights of stairs or by a lift.
To help guide you once there the Canberra Birds Sandwich Boards will be outside the front door.
For people attending the meeting by public transport, the R10 bus provides a very good service around every 15 minutes from the ANU through Civic to the Denman Prospect shops
with the bus stop opposite the venue. For example, a bus runs to there from 6:57 to 7:23 pm and return buses at 9:05 or 9:35 pm arriving at the ANU at 9:31 and 10:01 pm, respectively.
At the August meeting there will be three presentations, the first a shorter one than usual, then followed by 2 longer presentations on aspects of bioacoustics
recording.
The first will be by
Gang-gang editor Zac Flegg providing a “Canberra Bird Blitz Summary”
The Canberra Birds Blitz is a long-running annual survey project that began in 2005 and aims to cover the entire range of the ACT; providing a snapshot of the species that call
the region home. In recent years, the project has been left without a coordinator, leading to what has now been termed the “Bird Blitz,
lite”. This quick presentation aims to provide an overview of the species detected during the last few years of the survey, changes in methodology and provide a call for coordinators.
The next speaker will be Dr Jurian Hoogewerff
of Hoog Consulting on “Introduction to technical aspects of ecoacoustic recording.”
Ecoacoustics encompasses a wide range of sound domains; geophony, biophony and anthrophony. Bioacoustics focusses on how animals make use of sound and how they respond to all
sounds. Most animals have a similar frequency hearing range as humans about 20 Hz to 20 kHz or slightly higher but produce sound in a constrained range.
Recording sound pressure waves requires a sensitive variable pressure sensor, a microphone, to translate the small air movement into a variable electric current. The weak low
voltage signal from the microphone needs to be amplified.
The amplified signal is nowadays converted to a digital signal, using an analog to digital converter, an “ADC”. The ADC sampling rate needs to be at least twice the highest required
sound frequency (so-called Nyquist frequency) to obtain a useable digital representation. Another key parameter in the digitisation is the resolution in which the amplitude of the sound wave is sampled, called the bit depth. A 16-bit bit depth gives 216
= 65,536 steps resolution and is the typical CD quality. The digital data stream is subsequently captured by writing to a file on a disk or memory stick.
The first complete-package all-weather battery-operated time-lapse sound recorders (microphone + amplifier + ADC + sd card writer + CPU) that were easy to operate were the “Songmeters”
made by Wildlife Acoustics in the USA in 2007 at a A$1500 price point. Since then, competitors, like Frontier Labs from Brisbane in 2011 have come on the market and driven significant quality improvements. In 2017 the open source Audiomoth recorder set a new
standard for cheap miniature recorders (A$100) and other manufacturers are copying and improving the design and capabilities. In the presentation more technical details and software to inspect the large amount of data produced when recording in time-lapse
mode for weeks will be explained.
This will be followed by
Zac Flegg on “Nightjars in the Cotter—Methods, Findings and Ethical Implications”
This presentation overviews a recent research project run over the summer of 2025-2026. Using Passive Acoustic Monitoring (PAM), the
White-throated Nightjar and other nocturnal species were recorded. This project was a direct response to recent
records within the COG Area of Interest (AoI), combined with a lack of quality data surrounding local Nightjar stay and calling patterns. The project successfully recorded a total of 112 distinct species. This included regionally interesting species such as
Powerful Owl, Red-capped Robin
and
Brush Bronzewing. This underlines the potential application of audio recording as an environmental monitoring tool.
One key finding of the project was high levels of playback use around the Cotter during the study period - often for hours at a time and for almost a quarter of the study period.
At a time when Nightjars are known to breed, the potential impact of this action cannot be overstated. This presentation will conclude by outlining the outcomes of the project. This includes the development of a custom AI model training for Nightjar call recognition.
