Acoustic sensors enable efficient and non-invasive monitoring of a wide range of species, including many that are difficult to monitor in other ways. Although they were initially limited in application scope largely due to cost and hardware constraints, the development of low-cost, open-source models like the Audiomoth in recent years has increased access immensely and opened up new avenues of research. For example, some teams are using them to identify illicit human activities through the detection of associated sounds, like gunshots, vehicles, or chainsaws (e.g. OpenEars).
With this relatively novel dimension of wildlife monitoring rapidly advancing in both marine and terrestrial systems, it is crucial that we identify and share information about the utility and constraints of these sensors to inform efforts. A recent study identified advancements in hardware and machine learning applications, as well as early development of acoustic biodiversity indicators, as factors facilitating progress in the field. In terms of limitations, the authors highlight insufficient reference sound libraries, a lack of open-source audio processing tools, and a need for standardization of survey and analysis protocols. They also stress the importance of collaboration in moving forward, which is precisely what this group will aim to facilitate.
If you're new to acoustic monitoring and want to get up to speed on the basics, check out these beginner's resources and conversations from across the WILDLABS platform:
Three Resources for Beginners:
- Listening to Nature: The Emerging Field of Bioacoustics, Adam Welz
- Ecoacoustics and Biodiversity Monitoring, RSEC Journal
- Monitoring Ecosystems through Sound: The Present and Future of Passive Acoustics, Ella Browning and Rory Gibb
Three Forum Threads for Beginners:
- AudioMoth user guide | Tessa Rhinehart
- Audiomoth and Natterjack Monitoring (UK) | Stuart Newson
- Help with analysing bat recordings from Audiomoth | Carlos Abrahams
Three Tutorials for Beginners:
- "How do I perform automated recordings of bird assemblages?" | Carlos Abrahams, Tech Tutors
- "How do I scale up acoustic surveys with Audiomoths and automated processing?" | Tessa Rhinehart, Tech Tutors
- Acoustic Monitoring | David Watson, Ruby Lee, Andy Hill, and Dimitri Ponirakis, Virtual Meetups
Want to know more about acoustic monitoring and learn from experts in the WILDLABS community? Jump into the discussion in our Acoustic Monitoring group!
Header image: Carly Batist
International Union for the Conservation of Nature (IUCN)
Key Biodiversity Areas Programme Officer, IUCN
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- @chenxing3
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- @capreolus
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Capreolus e.U.
wildlife biologist with capreolus.at
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- @affiliatepurna
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Purna Man Shrestha is a program coordinator of mountain spirit, Nepal. He has 6 years of working experience in human wildlife interaction focusing on wildcats, and conflicts. He has a good knowledge on wildlife survey techniques, field survey, stakeholder engagement
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WILDLABS & Fauna & Flora
I'm the Platform and Community Support Project Officer at WILDLABS! Speak to me if you have any inquiries about using the WILDLABS Platform or AI for Conservation: Office Hours.
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- @CDean
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Grad Student, UW-Stout, Beaver habitat biodiversity research, process based restoration
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Holder of BSc in Applied Zoology. Ecologist at Ruaha National park
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An Environmental sciences and Management graduate from SUA, passionate and eager to drive change to the Environment, making World a better place for present and future generations.
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I'm a software developer. I have open source projects in practical object detection and alerting that is well suited for poacher detection and a Raspberry Pi based sound localizing ARU project
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Aarhus University
Biologist and Research Technician working with ecosystem monitoring and research at Zackenberg Research Station in Greenland
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Assiniboine Park Conservancy
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Do you know anyone interested in this position? Let them know by sharing widely.
27 February 2024
The Ecological Acoustics and Behavior Lab at the University of New Hampshire seeks a PhD student to join our lab to investigate how forest habitat affects moose occupancy and soundscape in northern New Hampshire
13 February 2024
The primary focus of the research is to explore how red deer movements, space use, habitat selection and foraging behaviour change during the wolf recolonization process.
10 February 2024
Applications open for a PhD position in plant vibroacoustics at the University of Southampton
8 February 2024
We demonstrate the power of using passive acoustic monitoring & machine learning to survey species, using ruffed lemurs in southeastern Madagascar as an example.
23 January 2024
Come join our team! We're looking for a Program Officer to join the WILDLABS Community, hosted by WCS in Argentina. This role will support our research program, with the chosen candidate leading our horizon scanning...
22 January 2024
Careers
We're hiring ecologists for immediate start / remote working / short contract
19 January 2024
Two years in Cape Town, South Africa. Yearly visits to Rwanda. If you love to code, and all things Python/deep learning/tech stuff/ then you'll have an awesome time!
16 January 2024
This article discussed early work on modeling how acoustic properties of the environment will change with variations in weather.
9 January 2024
Analysing recordings of gunshots could help save endangered species around the world by identifying poacher hotspots.
7 January 2024
Digital monitoring tools are helping rangers protect wildlife in South America's Atlantic Forest. Could sound-based maps pin down the poaching threat?
7 January 2024
The IQOE Task Team on Low-Cost Hydrophones for Research, Education, and Citizen Science is looking for industry partners to develop a low-cost hydrophone.
15 December 2023
July 2024
event
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43 Products
Recently updated products
Description | Activity | Replies | Groups | Updated |
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Fantastic!! |
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Acoustics, AI for Conservation, Biologging, Build Your Own Data Logger Community, Community Base, Early Career, Ethics of Conservation Tech, Marine Conservation, Open Source Solutions | 5 seconds ago | |
If you search Digikey for a 'strain relief' you should be able to find a rubber grommet that will hold that mic without any additional machining. A blob of silicone will adhesive... |
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Acoustics | 2 weeks 2 days ago | |
Thanks Carly! I had reviewed some of the help files, but clearly not the right ones!My email is [email protected] |
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Acoustics, Software and Mobile Apps | 2 weeks 3 days ago | |
Hi Tabitha, What recording settings were you using when you saw these differences? I've measured the consumption across some different firmware versions and I can't see any... |
+10
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Acoustics | 3 weeks ago | |
Wow.. Really exciting to see this effort. Congratulations on the award!I have been interested in this subject for a long time, as we have elephant-human conflicts in plenty in... |
+7
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Acoustics | 3 weeks 5 days ago | |
Hello!Long time, no update. @StephODonnell suggested I post here with my thesis and some reflections. ---------------------------------------------------------TL;DR... |
+19
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Acoustics | 1 month ago | |
I think I've landed on the Wildlife Acoustics Song Meter Mini Bat 2 for now, but I'm definitely interested to see how this cheaper tech progresses |
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Acoustics | 1 month ago | |
Hi Jesse,For a material to be acoustically transparent (in air), the speed of sound in the material times its density must match that of air. Realistically, any solid... |
+1
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Acoustics, Biologging | 1 month ago | |
Hi Steph, We appreciate the support! Thanks for the tag and your help managing the community!Patrick |
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Sensors, Acoustics, Conservation Dogs, Emerging Tech, Open Source Solutions | 1 month ago | |
Hi Sol,If the maximum depth is 30m, it would be worth experimenting with HydroMoth in this application especially if the deployment time is short. As Matt says, the air-filed case... |
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Acoustics, AI for Conservation, Data management and processing tools, Emerging Tech, Sustainable Fishing Challenges | 1 month ago | |
Oh wow, thank you so much!!!I will keep that four advices in mind! |
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Acoustics | 1 month 1 week ago | |
You won't get any audio if you don't allow enough time for the hydromoth/audiomoth to write. So when you do a continuous recording you need to experiment a little. I'm sure there... |
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Acoustics | 1 month 1 week ago |
VIHAR-2024 deadline extension, June 30th (Interspeech satellite event)
5 June 2024 10:30am
7 June 2024 8:29am
hi Alex!! I already posted the event, I just wanted to posted an update: the deadline was extended.
7 June 2024 1:45pm
Fantastic!!
New WildLabs Funding & Finance group
5 June 2024 3:24pm
5 June 2024 4:14pm
6 June 2024 1:38am
6 June 2024 4:16am
Apply! 2024 Conservation Tech Award
3 June 2024 3:51pm
Bioacoustics and AI 101
29 May 2024 2:21pm
4th African Bioacoustics Community Conference
29 May 2024 1:50pm
2nd Colombian Congress on Bioacoustics and Ecoacoustics
28 May 2024 9:20pm
XIII Congreso Iberoamericano de Acústica
28 May 2024 9:07pm
9th Workshop On Detection and Classification of Acoustic Scenes and Events
28 May 2024 8:57pm
32nd European Signal Processing Conference
28 May 2024 8:44pm
5th World Ecoacoustics Congress
28 May 2024 8:07pm
Mounting Electret Microphone
20 May 2024 6:20pm
24 May 2024 6:03pm
If you search Digikey for a 'strain relief' you should be able to find a rubber grommet that will hold that mic without any additional machining. A blob of silicone will adhesive and waterproof, I always like stuff to do at least two things. It's also vibration reducing on the mic. You may want to either 'shotgun' mic by putting it at the end of a tube, that will block a lot of ambient also. Unless it whistles like a bottle in the wind, that might be a problem later lol. Or use a dish as a focus.
Uploading External Recordings for Templates?
23 May 2024 4:52pm
23 May 2024 9:15pm
Hi Cortney!
I'm Carly, the Science Outreach Lead at Arbimon :)
I wanted to just point out that we have support docs and help pages at help.arbimon.org and also a link to contact us directly for help!
Regarding the error you're getting with the upload, it's probably easiest to switch over to email so I can get more information on the project and look into it on the backend. I would also recommend using the Uploader App rather than the web uploader, if you're not already.
But your idea is correct, we have many users who import renamed Xeno-Canto files to Arbimon to use as templates!
What's your email? We can continue the convo to get you set up!
23 May 2024 10:27pm
Thanks Carly! I had reviewed some of the help files, but clearly not the right ones!
My email is [email protected]
Audiomoth Energy consuption estimates
4 March 2024 12:25pm
16 May 2024 9:34pm
We had this same issue, and found that the firmware version 1.9.2 was our issue. We bumped it back to 1.9.0 and our energy consumption was back to normal.
We record data for 7 hours a day (3.5 hour blocks), using sandisk extreme 64GB micro SD cards. We don’t use re-chargeable batteries, and the ARUs are set for 14-day periods before being collected. With the 1.9.2 firmware, for some reason they’d only record for maybe 9 days tops before dying. At firmware 1.9.0, we were back to our normal recording of minimum 14 days (although they often last longer). We tried different batteries, different energy saving settings, nothing worked besides bumping the firmware down. This issue was in both our brand new AudioMoths and 2-year old AudioMoths.
I hope this helps.
17 May 2024 11:42am
Very helpful! Thank you, I'll try that.
19 May 2024 11:27am
Hi Tabitha, What recording settings were you using when you saw these differences? I've measured the consumption across some different firmware versions and I can't see any difference. Were these AudioMoth 1.2.0 devices? Alex
Share Your Work in a Conservation Technology Video
17 May 2024 9:06pm
WILDLABS AWARDS 2024 - Developing AudioMoth for the detection of infrasonic elephant rumbles
11 April 2024 7:35am
13 May 2024 8:28am
Hi Alex,
Very cool, that would give us lots of room for collaboration since we are focussing on model development taking hardware restrictions and inference speed into account.
14 May 2024 12:49pm
Wow.. Really exciting to see this effort. Congratulations on the award!
I have been interested in this subject for a long time, as we have elephant-human conflicts in plenty in India (my country). Sometime back I had hacked a computer optical mouse as a seismic detector in order to study elephant intrusion into farmlands (where they are considered as pests). But I think we need more robust detectors. I am also considering laser led self-mixing as a technique to get a good alternative to expensive geophones. Wish you all the very best.
14 May 2024 12:50pm
Wow.. Really exciting to see this effort. Congratulations on the award!
I have been interested in this subject for a long time, as we have elephant-human conflicts in plenty in India (my country). Sometime back I had hacked a computer optical mouse as a seismic detector in order to study elephant intrusion into farmlands (where they are considered as pests). But I think we need more robust detectors. I am also considering laser led self-mixing as a technique to get a good alternative to expensive geophones. Wish you all the very best.
Survey on European biodiversity monitoring communities
7 May 2024 3:39pm
Biodiversa+ is running a survey to map the European biodiversity monitoring landscape, identify opportunities for collaboration, and strengthen coordination for improved monitoring.
Advice on a Master's project
4 August 2020 2:07pm
10 March 2021 8:03pm
Yes. The key output for synchronisation is the pulse per second (PPS) output which is synchronised very accurately to UTC. The TX from the GPS module is then useful for reading the time and positions. You generally don't need to be able to send commands to the module as most of the time the default settings are fine.
18 March 2021 5:26pm
Hi Harry (and all)
Just wanted to share some potentially relevant papers that I've come across, in case you haven't found them already. Coming more from the ecology/conservation focused side of conservation tech, but potentially of use to see what's actually been deployed out there!
Yip, D. A., Knight, E. C., Haave‐Audet, E., Wilson, S. J., Charchuk, C., Scott, C. D., ... & Bayne, E. M. (2020). Sound level measurements from audio recordings provide objective distance estimates for distance sampling wildlife populations. Remote Sensing in Ecology and Conservation, 6(3), 301-315. https://zslpublications.onlinelibrary.wiley.com/doi/pdfdirect/10.1002/rse2.118.
Abadi, S. H., Wacker, D. W., Newton, J. G., & Flett, D. (2019). Acoustic localization of crows in pre-roost aggregations. The Journal of the Acoustical Society of America, 146(6), 4664-4671. https://asa.scitation.org/doi/full/10.1121/1.5138133.
Spillmann, B., van Noordwijk, M. A., Willems, E. P., Mitra Setia, T., Wipfli, U., & van Schaik, C. P. (2015). Validation of an acoustic location system to monitor Bornean orangutan (Pongo pygmaeus wurmbii) long calls. American Journal of Primatology, 77(7), 767-776. https://doi.org/10.1002/ajp.22398.
Kershenbaum, A., Owens, J. L., & Waller, S. (2019). Tracking cryptic animals using acoustic multilateration: A system for long-range wolf detection. The Journal of the Acoustical Society of America, 145(3), 1619-1628. https://doi.org/10.1121/1.5092973.
Stinco, P., Tesei, A., Dreo, R., & Micheli, M. (2021). Detection of envelope modulation and direction of arrival estimation of multiple noise sources with an acoustic vector sensor. The Journal of the Acoustical Society of America, 149(3), 1596-1608. https://doi.org/10.1121/10.0003628.
Rhinehart, T. A., Chronister, L. M., Devlin, T., & Kitzes, J. (2020). Acoustic localization of terrestrial wildlife: Current practices and future opportunities. Ecology and Evolution, 10(13), 6794-6818. https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.6216.
4 May 2024 3:33pm
Hello!
Long time, no update. @StephODonnell suggested I post here with my thesis and some reflections.
---------------------------------------------------------
TL;DR
My thesis looked into the effects of environmental parameters like wind, temperature, and vegetation on acoustic classification and localisation of terrestrial wildlife, aiming to shed light on the implications for study design.
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Summary
My thesis centred on improving acoustic data acquisition via an analysis of the physics of sound propagation. The idea driving this was that there isn't enough attention paid to environmental effects on sound. The hope was that this could be used to improve the design of acoustic monitoring systems. COVID shifted the direction away from any practical work, but thankfully we managed to find our way through it by using data within the literature.
The thesis is split into two main sections:
- Improving SNR for sound classification:
I explored environmental factors affecting SNR and their implications for the detection space of a signal.
I've briefly had a look through updates in the field since my thesis, and there is a great paper here. This paper takes a similar approach but does so far more elegantly and completely - definitely worth exploring!
- Error Analysis in Sound Localisation:
I explored how differing environmental conditions from those assumed can influence the TDOA error on a microphone pair, and thus position error. The main parameters looked at were temperature, humidity, wind speed & direction and 2D model error.
Conclusion
I ended with some recommendations for system design such as adding additional sensors for more intelligent monitoring systems, or how to maximise the study area by maximising your SNR.
I also discussed future work. The dream output would have been taking the analysis in the thesis and creating an online tool to be used to optimise sensor placement. Practitioners could use it to quickly input their study features to determine the likely important parameters for their deployment location, and how they can improve data quality. This would involve taking the analysis in the thesis and packaging it into an app - I'm thinking R Shiny or similar.
---------------------------------------------------------
Thoughts
In the end, I felt that it took a long time to figure out a direction for the project , and how to actively contribute to the space. It was (obviously) difficult as I didn't come into this with prior knowledge or a structured plan, and so I was a little disappointed with the outcome. It would have been great to explore some of the things I put down as "future work" - but I guess that's part of the process.
The project was a great intersection of technology and environment and it definitely helped shape the next few years for me. Since finishing I have taken a couple of detours into the workforce. First to a marine robotics company, and then measuring forest carbon with LiDAR. I've now just started a PhD using ocean modelling to map biodiversity in the ocean with an AUV. So despite the challenges in trying to design a project within my interests, it has been pretty foundational for me going forward!
Thanks to everyone that offered help and advice. Likewise, I'm very happy to answer any questions from other students/anyone, and I'm really looking forward to being back in the wildlife tech space!
Harry
Thesis available here.
Affordable acoustic monitors for "whispering" bats?
30 April 2024 8:31pm
30 April 2024 11:28pm
Also some other bat experts I'd recommend reaching out to, if you haven't already (for this and any bat acoustic questions) - Adrià López-Baucells, Nils Bouillard, Kate Jones, Stuart Newson, plus obviously anyone at the big orgs like Bat Conservation Int'l, etc.
3 May 2024 3:28pm
Hey @ccosma if you are interested in multiple cheap sensors, Phil Atkin and I are making initial batches of pippyG bat detector. They can record 4-7 days at the moment, but could be modified to fit needs.
3 May 2024 9:04pm
I think I've landed on the Wildlife Acoustics Song Meter Mini Bat 2 for now, but I'm definitely interested to see how this cheaper tech progresses
Acoustically Transparent Epoxy
26 April 2024 3:26pm
1 May 2024 5:35pm
Same issues here. A MEMS is a great idea to pot, but you really need a piezoelectric element for this to work and not a MEMS based on capacitance (btw they're all capacitance, except for one now discontinued...). It was originally made by Vesper, but the company was bought out last year and the MEMS is no longer made.
This is because you're no longer really doing a typical microphone, this would be a contact type hydrophone. For waterproofing, you can actually get a waterproof MEMS. As long as your not submerging this for an extended period, it should do the job. Be sure to keep the cable short between the PCB and the mic as you'll get noise as I've experienced.
For generally answering your question on the "best" epoxy to with sound transparency, in general the harder the material the lower the acoustic impedance. I use Epotec 301 resin with a hardness of 85. Your shape will also influence the resonance frequencies, meaning the flat frequency response will now be distorted and you'll probably have distorted audio. .
3 May 2024 1:25am
You generally don't want to pot MEMS microphones since they're designed to pick up on air pressure changes and adding any material in front of the microphone just introduces another transition layer where pressure waves need to propagate through. Also, potting the MEMS microphone can be tricky since if you get any material in the port, you could damage the microphone or drastically reduce its performance. If you want to seal something with epoxy, take a look at contact microphones. Higher frequencies will be attenuated but depending on the application, it could work.
There are companies, however, that design fabrics that are waterproof/resistant but have a relatively low acoustic impedance. SAATI has a variety of samples that you can request and GORE makes Acoustic Vents that could work. You can design a mechanical housing around your MEMS microphone with small perforations that are covered by one of these materials. I did this for one of my latest projects and it holds up just fine in heavy rain conditions.
3 May 2024 5:34pm
Hi Jesse,
For a material to be acoustically transparent (in air), the speed of sound in the material times its density must match that of air. Realistically, any solid material will have a greater density than air, and a higher speed of sound to boot, so I'm afraid there's no way to match it to air. Sorry.
CollarID: multimodal wearable sensor system for wild and domesticated dogs
3 May 2024 1:42am
3 May 2024 10:14am
Hi Patrick,
This is so cool, thanks for sharing! It's also a perfect example of what we were hoping to capture in the R&D section of the inventory - I've created a new entry for #CollarID so it's discoverable and so we can track how it evolves across any mentions in different posts/discussions that come up on WILDLABS. This thread appears on the listing, and I'll make you three the contacts for it too. But please do go in and update any of the info there as well!
Steph
3 May 2024 2:01pm
Hi Steph,
We appreciate the support! Thanks for the tag and your help managing the community!
Patrick
Drop-deployed HydroMoth
2 April 2024 10:20am
15 April 2024 6:53am
Hi Matthew,
Thanks for your advice, this is really helpful!
I'm planning to use it in a seagrass meadow survey for a series of ~20 drops/sites to around 30 m, recording for around 10 minutes each time, in Cornwall, UK.
At this stage I reckon we won't exceed 30 m, but based on your advice, I think this sounds like not the best setup for the surveys we want to try.
We will try the Aquarian H1a, attached to the Zoom H1e unit, through a PVC case. This is what Aquarian recommended to me when I contacted them too.
Thanks for the advice, to be honest the software component is what I was most interested in when it came to the AudioMoth- is there any other open source software you would recommend for this?
Best wishes,
Sol
21 April 2024 7:10pm
Hey Sol,
No problem at all. Depending on your configuration, the Audiomoth software would have to work on a PCB with an ESP32 chip which is the unit on the audiomoth/hydromoth, so you would have to make a PCB centered around this chip. You could mimic the functionality of the audiomoth software on another chip, like on a raspberry pi with python's pyaudio library for example. The problem you would have is that the H1A requires phantom power, so it's not plug and play. I'm not too aware with the H1e, but maybe you can control the microphone through the recorder that is programmable through activations by the RPi (not that this is the most efficient MCU for this application, but it is user friendly). A simpler solution might be to just record continuously and play a sound or take notes of when your 10 min deployment starts. I think it should last you >6 hours with a set of lithium energizer batteries. You may want to think about putting a penetrator on the PVC housing for a push button or switch to start when you deploy. They make a few waterproof options.
Just somethign else that occured to me, but if you're dropping these systems, you'll want to ensure that the system isn't wobbling in the seagrass as that will probably be all you will hear on the recordings, especially if you plan to deploy shallower. For my studies in Curacao, we aim to be 5lbs negative, but this all depends on your current and surface action. You might also want to think about the time of day you're recording biodiversity in general. I may suggest recording the site for a bit (a couple days or a week) prior to your study to see what you should account for (e.g. tide flow/current/anthropogenic disturbance) and determine diel patterning of vocalizations you are aiming to collect if subsampling at 10 minutes.
Cheers,
Matt
3 May 2024 12:55pm
Hi Sol,
If the maximum depth is 30m, it would be worth experimenting with HydroMoth in this application especially if the deployment time is short. As Matt says, the air-filed case means it is not possible to accurately calibrate the signal strength due to the directionality of the response. For some applications, this doesn't matter. For others, it may.
Another option for longer/deeper deployments would be an Aquarian H2D hydrophone which will plug directly into AudioMoth Dev or AudioMoth 1.2 (with the 3.5mm jack added). You can then use any appropriately sized battery pack.
If you also connect a magnetic switch, as per the GPS board, you can stop and start recording from outside the housing with the standard firmware.
Alex
Your HydroMoth experience!
29 July 2022 1:38pm
1 May 2024 5:45pm
Vinegar is also a great solution! Let it sit overnight and then just scrub it off. As a warning if you don't clean it, your sensitivity does decrease. You might actually see this if you keep it out there for a month that the amplitude of your calls decrease over the month/you might detect fewer calls.
1 May 2024 5:51pm
Hey! I would recommend a few things:
1) set up at least two in the same site kind of back to back or side to side if you have that many. Directionality can influence the number of calls you get and it's just good to know your error rate.
2) Experiment with breaks and recording duration. You wont collect anything if the write time is not long enough to record to your SD card and you'll get empty files.
3) Clean your device every time you take it out or see visible biofouling. Also, add silicon grease every time to your O-ring. Take it out with an O-ring pick and clean the plastic seal, looking for any type of sand/mud/debris. We've had a few flooding incidences, but this is probably because we open them all the time.
4) lower the frequency rate the more data you can collect, so keep it as low as your frequency of interest without clipping your calls. Fish are lower than pretty much everything (2kHz-3kHz).
I hope this helps!
2 May 2024 6:45pm
Oh wow, thank you so much!!!
I will keep that four advices in mind!
Hydromoth settings
9 May 2022 5:03pm
11 August 2023 8:10pm
Hi Ian,
I have hours of an unidentified creature recorded during overnight recording sessions with mutliple hydrophones. We think it is platypus but there is nothing to compare against that isn't from captive sounds. I am waiting on the Hydromoth to become available again so I can do longer term monitoring.
1 May 2024 5:26pm
Hi everyone, I just got my first hydromoth and wanted to test it for aquatic soundscape with interest in Tomistoma, Otter, boat traffic and maybe fishes too! But before that I maybe test it on zoos.
What are your advices, tips, or suggestion for first-time user? thank you!
1 May 2024 5:42pm
You won't get any audio if you don't allow enough time for the hydromoth/audiomoth to write. So when you do a continuous recording you need to experiment a little. I'm sure there is a formula to calculate this, but I haven't figure that out. I typically do 5 min recordings with 10 seconds of write/break time. I think this system is expecting you to subsample, so keep that in mind instead of a continuous recording.
I do 8kHz sampling and get about 7 days of data and then the voltage gets too low and you start getting SD card write errors and missing files.
In terms of analysis, I've had trouble understanding the directionality of the hydromoth and incorporating this into my studies. I always set up two at the same site to check the variability in my call detections and include this into my error analysis.
WILDLABS AWARDS 2024 - Underwater Passive Acoustic Monitoring (UPAM) for threatened Andean water frogs
30 March 2024 3:54pm
5 April 2024 12:13pm
Congratulations, very exciting! Keep us updated!
7 April 2024 6:09pm
This is so cool @Mauricio_Akmentins - congrats and look forward to seeing your project evolve!
1 May 2024 5:17pm
Congratulations! My first hydromoth was just arrived yesterday and so excited! Looking forward for the update from your project!!!
The Inventory User Guide
1 May 2024 12:46pm
Introducing The Inventory!
1 May 2024 12:46pm
2 May 2024 3:08pm
3 May 2024 5:33pm
17 May 2024 7:29am
Hiring Chief Engineer at Conservation X Labs
1 May 2024 12:19pm
Attaching a directional microphone to a Wildlife Acoustics ultrasonic recorder?
29 April 2024 4:47pm
30 April 2024 4:28pm
Hi Luke, sounds like an interesting project! One thing to note is the ultrasonic Wildlife Acoustics unit you're looking at is already fairly directional. Take a look at the horizontal directionality plot towards the bottom:
You can see that for the relevant frequencies for slow lorises ultrasonic calls (40-60 kHz), there is 25-30 dB difference between 0 and 180 horizontal degrees. It's not perfect, but is close to some directional mics, and if it works well enough for your project it would save a lot of time and testing!
If you do choose to integrate an external directional microphone, be careful with microphone placement to avoid potential ultrasonic reflections from any hard flat surface like a tree trunk, water surface, or the instrument housing itself. Here's an example of some echo calls from reflective surfaces from bat vocalizations:
It would be helpful to hear how you plan on obtaining behavioral information (and what kind) to correlate with vocalizations? Observations, cameras, biologgers, etc.? This could inform responses a bit more.
30 April 2024 6:19pm
Hi Jesse,
Thank you so much for your reply and for the fantastic knowledge and resources! I was unfamiliar with the plots, so thank you for providing some interpretation- I will have to work to better understanding them. This may change things (I was going off of experience from field work with the last iteration of this WA recorder which had omnidirectional recording) and I may choose to pilot the recorder without an external microphone this summer.
Regarding my plan for collecting behavioral data, I plan to follow 15 wild individuals in a reserve in Thailand (mostly dry evergreen and dry dipterocarp forest with some human modified areas). I intend to use instantaneous focal sampling to observe lorises in two shifts between 18:00-06:00h. During these focal follows I will record all behaviors at 5-min intervals and use all-occurrences sampling for social and feeding behaviors, using an established slow loris ethogram. Simultaneously, I plan to record vocalizations, with the help of a research assistant and field guide. So we will be carrying the recorder with us during behavioral data collection. I intend to match up the timestamped loris vocalizations with the behavioral data to understand the call's function.
30 April 2024 7:00pm
If you have the resources, I would suggest testing the sensitivity and directionality of the system at relevant frequencies both with and without an external mic, and let the results dictate which will be best for your case study.
Another thing to think about since you are manually taking the recordings is if a WA unit is really necessary. You're paying for the technology of a remote system without needing it. Other cheaper handheld recorders (such as Zoom recorders) could free up $$ for a higher quality directional microphone. Although of note is that common Zoom recorders like the H4n only sample up to 96kHz for which the upper frequency limit (48kHz) is getting very close to the frequencies you're likely wanting to measure.
The Bat Conservation Trust - Research Scientist (Quantitative ecology)
24 April 2024 7:29pm
5 June 2024 3:05pm
Thanks for sharing this @nkundiushuti ! I think this post would be better suited as an event, that way it will show up on the WILDLABS event calendar page. Let me know if you have any questions on how to make an event post! You just click the +Post button in the top right corner, then click "event."