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Nature's Voice: Building a Global Library of Biodiversity Sound

This expedition aimed to document the sounds of the highly endangered Colombian Amazon Rainforest and create a comprehensive digital audio library of rare natural environments. Advanced audio equipment was used to capture the sounds, which were then edited and organised with detailed metadata, including recognised bird species names embedded within each recording. The resulting audio library, which includes recordings of numerous bird species, monkey and jaguars, was made available for scientific research purposes to local Colombian universities and other researchers working in the field of bioacoustics. Additionally, sections of some recordings were shared on EarthFM, an online platform holding a vast collection of nature sounds recorded by various artists from around the world. The full audio library is also being added to a website, Earth Experience, offering a unique opportunity for the public to listen and learn about the biodiversity and bioacoustics of these largely unknown and inaccessible areas.

Submitted on 3 February 2023

Case Author

Jan Brelih

Earth Experience

Key takeaways

There are still vast expanses of pristine rainforest left, but also sizable areas of complete destruction, and this degradation is getting worse every day.

The recordings captured both undisturbed and disturbed acoustic environments for comparison, with the latter presenting much quieter and less varied soundscapes. This striking auditory difference highlights the significance of preserving natural ecosystems in a new way. Although the flora cannot be heard,  the crucial role of trees is loud and clear, as they play an important role in biodiversity. Important practical experience was gained through the use of digital technology and actually doing audio production in the most difficult of conditions. Beyond discovering these hidden ecosystems and bird species by sound alone, many other lessons were learned that are significant to bioacoustic research.

  • The importance of using professional audio recording equipment capable of functioning in challenging outdoor conditions, such as those found in remote and endangered natural habitats.
  • The importance of preparing a detailed plan for navigating difficult terrain and protected areas during the expedition.
  • The importance of understanding local culture and customs to ensure better communication and cooperation with local communities.
  • The importance of being able to recognize bird species and their sounds, as it will make it easier to accurately document the sounds of remote and endangered natural habitats.
  • The use of digital technology in the field, such as editing software, storage and sharing of the audio libraries in a productive way.
  • Digital audio editing, compiling and audio metadata.

Key issues

  • Rainforest destruction
  • Navigating the difficult terrain and protected areas during the expedition
  • Requesting and getting permission to enter the rainforest area from Colombian guerilla fighters
  • Keeping the audio equipment safe

Case target / aim / intention

The journey documented the sounds of remote and endangered natural habitats in order to create a digital audio library / collection for the public to appreciate the beauty and give a new sense of the importance of preserving such places. Further,  universities and the scientific community now have access for deeper bioacoustic research.

Case Study

Part One

Initial Situation

Isolated and endangered natural ecosystems are by nature unknown, and this was an attempt to document them in a new way.

These remote and inaccessible habitats  are under threat from human activities such as logging, mining and agriculture. The project captured, compiled and presented the sounds of such habitats in order to raise awareness about the importance of conservation and to give auditory access to the general public and the scientific community.

The initial idea was to use professional audio equipment to record the sounds of various bird species and other wildlife thriving there. The researchers mounted an expedition to these ecosystems to record the soundscape with specialised equipment, and then edit and compile the recordings into a digital audio library. The expedition was self-funded, to the tune of €3000 for field activities alone. Travel gear, audio gear and post-editing drove up costs to more than €8000.

The project was conducted in a remote and endangered natural habitat, which presented challenges in terms of accessibility and logistics.

Jan, the case author, in the jungle

Part Two

Strategy and implementation

The project's strategy and implementation began with finding  suitable locations, followed by audio recording equipment setup and the actual recording of the sounds. The project faced several challenges during the expedition, including harsh weather conditions, difficult terrain and navigating long detours around protected areas. Despite these challenges, a wide range of sounds from various remote habitats was successfully captured.

After the long expedition, I returned to the studio to edit and compile the recordings. I listened to the sounds carefully and classified them into audio libraries annotated with metadata, such as the names of bird species. I then shared the audio libraries with universities and the scientific community for further bioacoustic research.

At first, from the very sparse information online, it seemed to be almost impossible or very dangerous to go reach the Colombian Amazon overland. Drug traffickers and guerilla fighters operate throughout these areas. Nevertheless, I was determined to try, to put myself and all the equipment at risk in order to reach the desired results. The whole situation and personal experience ended up surprisingly different and positive. In my whole time in the field, moving through these dangerous areas, neither the local people nor rebels threatened me in the slightest. I did indeed meet some guerillas. The whole experience was very positive and not as dangerous as I had assumed. Who would know guerillas could be so nice?

I was, due to my previous experience, equipped with the necessary knowledge and expertise to handle the challenges facing me. Additionally, partnerships were formed with local organisations to share the recording results

Technical scope:
The technologies involved in the project included professional audio recording equipment, editing software, and the storage and sharing of the audio libraries.

Recording gear:

  • MixPre II Sound Devices audio recorder
  • Audio Technica AT4022 omni-directional microphones

Audio editing software:

  • Adobe Audition
  • RX Pro Audio Editor
  • FabFilter EQ

Audio library:

  • 2 to 8 minute edited files
  • .Wav format
  • Khz 192

Product strategy and implementation started with the reconnaissance of potential locations followed by the selection of the best-suited location based on various factors such as accessibility, noise pollution and greatest biodiversity. Once the location was selected, the necessary equipment was assembled and tested to ensure its reliability and effectiveness in the field.

The next step involved setting up the recording equipment and conducting a series of tests to determine the ideal positioning, gain levels and microphone techniques to be used. The recording process itself was carried out with utmost care and precision to guarantee sound quality and avoid any human noise, interference or other undesirable auditory artefacts.

Throughout the project, various obstacles and challenges were encountered, such as weather conditions and technical issues, which required quick thinking and problem-solving skills. Despite these difficulties, the team was able to overcome them and successfully complete the recording process.


Post-recording, I listened to the audio carefully for unwanted noise and enhanced it with equalisation. I chose not to use noise reduction effects in order to maintain the sounds’ most natural, pristine state.

In the studio, Adobe Audition and the FabFilter EQ plugin were used for audio editing. The goal was to compile audio files between 1 to 6 minutes long with useful metadata.

To begin, the raw audio files were imported into Adobe Audition for editing. The FabFilter EQ plugin was then used to enhance the audio quality by adjusting the equalisation levels. This helped to achieve a more balanced and natural sound and remove low frequency spectrum.

Next, the edited audio files were trimmed to the desired length and organised into folders. The metadata, such as the recording location, date and description, was then added to each file. This information was important for keeping track of the recordings and for later reference.

Finally, the edited audio files were exported and saved in a format suitable for distribution, such as WAV or MP3. Throughout the editing process, attention was paid to detail to ensure that the audio was of the highest quality possible.

Case author Jan recording

Part Three

Outcome and reflection

Hindsight The expedition might have improved from a more specific plan for reaching the untamed rainforest. Some areas that seemed untouched on satellite maps had newly been deforested. To maximise productivity and time, local cargo planes visiting a remote Colombian Amazon are much more efficient yet more environmentally damaging. Before the journey, I found no online information regarding these aeroplane connections.

Navigating the regulations and communication in the areas visited was a significant challenge, especially as I did not work directly with the local government. Some of these areas are basically lawless, and I had to request permission to enter from Colombian guerilla fighters. I met with one of them, who assured me safe passage through the territory they operate in. The lack of government support in these areas made it even more crucial to establish good relationships with local communities for cooperation and assistance in navigating the terrain.

In order to reach remote and lawless areas, it's important to approach the local communities with respect and a clear intention. Locals are often more welcoming to outsiders who approach them with a genuine interest in their culture and environment. Taking the time to understand and appreciate the local customs and traditions can go a long way to build trusting relationships. It's also important to be aware of the potential impact that outsiders can have on the environment and the local way of life, and to take steps to minimise any negative impact.

  • Communication is key: ensure that you can communicate in the local language or have a local guide who can help you navigate the area and communicate with locals.
  • Connect with the local community: try to connect with local communities and individuals, such as hunters, fishermen and farmers who have knowledge about the area and can provide guidance and support.
  • Check rules and restrictions: when entering national parks or other protected areas, always check in advance about the rules and restrictions for visiting to avoid any legal or safety issues.
  • Handle necessary permissions: if you plan to reach protected areas that are not accessible or allowed for the public, make sure to connect with local government organisations and obtain the necessary permissions before proceeding.
  • Prioritise safety: ensure that you prioritise safety during your expedition by having proper equipment, experienced guides and emergency plans in place.
  • Be respectful of the environment and locals: show respect for the local environment and communities by minimising your impact on the area, following local customs and traditions, and maintaining good relationships with the locals.

Impact and efficiency The problem of lack of documentation and preservation of the sounds of remote and endangered natural habitats was addressed by the project, as the sounds were captured and preserved in the audio libraries. The cost-benefit ratio was achieved successfully. The impact of the project was satisfactory, as the audio libraries were shared with universities and the scientific community for further bioacoustic research, as well as being made available to the general public.

Added Value The project raised awareness about the importance of preserving remote and endangered natural habitats. It also had the potential to contribute to bioacoustic research, as the sounds captured in the project can now be used to study the impacts of human activities on natural habitats.

Reception The case was well welcomed by the public and scientific community, who were surprised that such an undertaking could be carried out successfully by a single person. The public also welcomed the project as it made the sounds of remote and endangered natural habitats accessible to them.

Success The project achieved its goal of capturing and producing the sounds of remote and endangered natural habitats without succumbing to any real dangers or safety issues, and then successfully putting together  high-quality audio libraries for research.

Rio Caqueta, Colombia

Author's notes

This experience has greatly increased my knowledge of the field, local cultures as well as the physical and psychological strength to complete such an undertaking.

Going alone to a foreign continent and country can be frightening, and the general perception of Colombian safety and issues did not help to put my mind at ease. However, my six-month stay in this country, which included visits to several inaccessible and officially dangerous regions, has proven to be mostly positive. The people I met  were welcoming and friendly. After such a long journey, I was excited to return to my studio and begin listening to and processing all of the captured sounds. It may be really exciting at times, when the mics were left in the jungle recording all night while I slept in my hammock nearby. Recording at night deep inside the Amazon near some clear-cut patches, I unwittingly captured my  biggest surprise. Later, while listening to the sounds, I heard the jaguar that was roaring and wandering near my camp and the microphones.

Lastly, I hope to continue documenting natural soundscapes from the  most secluded regions of the world. I'd like to eventually meet other people or form a team to undertake this work and share these moments in the field.