Soundscape Ecology: Opening your ears to conservation

The following article was published in Scottish Wildlife Magazine June 2019, issue 98, pp32-33 and is reposted with permission of Scottish Wildlife Trust.

When was the last time you stopped what you were doing and just listened? The sounds we hear can tell us much about our environment. On a spring day we might hear hungry chicks calling to be fed, children playing in the local park, a telephone ringing in a nearby house. All these sounds form a ‘soundscape’ unique to the location that you are in.

The term soundscape was coined by analogy with landscape to capture the idea that the sounds we perceive form a rich and nuanced acoustic environment. We can broadly categorise sound according to their origins. Sound created by birds, mammals, insects and other animals is termed ‘biophony’, while the sounds created by human activity is termed ‘anthropophony’. Soundscape ecology studies the relationships between these types of sound and how different organisms interact acoustically with their environment.

Many animals use sound to communicate within social groups: to attract a mate, to announce the arrival of a predator, for navigation and for territory holding. There is a rich tradition of scientists making field recordings of animal sounds across the globe, resulting in extensive audio libraries of environmental recordings covering many species – many now available online. With sound recording equipment improving all the time, it’s now possible to collect acoustic data around the clock, yielding rich information such as the presence and daily activity of certain species in a specific area. The technology has to date been used to monitor bats, birds, frogs, crickets, marine mammals, elephants and even some fish.

As well as studying specific species, researchers have tried to account for the way in which soundscapes are structured. For example, the ‘acoustic niche hypothesis’ proposes that animals such as birds and insects will tend to make their vocalisations stand out by pitching them at a frequency different to that used by other species that typically live alongside them. That is, the available frequency ranges somehow become shared out between species so that there is minimal overlapping.

It’s not surprising that there is evidence to suggest that the increasing noise that humans create, for example from road traffic and industrial activity, can have a negative effect on biodiversity. In the case of birds, anthropophony can block out sounds which signal danger and can also interfere with the messages that males use to defend their territory and to attract mates. Some species have learnt to compensate for this, with urban bird populations having different behaviours from their forest counterparts. One strategy exploits the so-called ‘Lombard effect’ – like humans at a cocktail party, birds will raise the volume of their sounds to overcome the background noise level. Other responses are to shift the time of singing activity to avoid urban rush hour, or to raise the pitch of songs to avoid them being drowned out by low-frequency traffic rumbles.

Reducing ambient noise is good for both humans and wildlife, yet mitigating the acoustic effects of road traffic – for example, by erecting noise barriers or making road surfaces more porous – is expensive and often not feasible in city centres. As well as reducing noise pollution in general, planners are recognising the importance of preserving and enhancing existing ‘quiet areas’, including parks and private gardens. From a wildlife conservation perspective, more research is required on the noise sensitivity of different animals and whether, for example, targeting noise reduction measures during the breeding season can achieve significant benefits.

In the CitySounds project, we set ourselves the goal of capturing a comprehensive ‘picture’ of an urban soundscape, using recording equipment located in trees. Initially, our focus was on the sounds that can be detected in the Meadows, a much-used city-centre greenspace in Edinburgh. Our follow-on project, ParkLife, has expanded the scope to embrace three other parks within the city and to also integrate information from social media about human use of the greenspaces. As well as looking for acoustic indicators of biodiversity, we are interested in the variety of sounds produced by human activities beyond background traffic: for example street music, festivals, recreational games, emergency sirens, and so on.

We are still in the process of collecting this unique and substantial soundscape dataset and although we have not carried out significant analysis of the data, we can begin to observe patterns. The image above spans six hours from midnight to 6am on 13 June 2018. Towards the right-hand side of the image, an increase in spectral activity is noticeable. This correlates to what we would expect around 4am on the morning in question — dawn was 3:56am in Edinburgh that day.

Longer term, we hope to be able to use artificial intelligence to detect and recognise different categories of events within a noisy city soundscape. This will give us more precise tools for understanding soundscape ecology, which in turn will help us be smarter and more effective in reducing our acoustic impact on the natural world.

CitySounds Talk at Smart Data and Smart Cities Conference

We presented an overview of the CitySounds project at the 3rd International Conference on Smart Data and Smart Cities in Delft on 4th October 2018. As you can see from the photo above, Delft was basking in warm autumn sunshine, so it was a great time for a visit.

Here’s the reference for the paper:

Klein, E., Chapple, S., Fainberg, J., Magill, C., Parker, M., Raab, C., & Silvertown, J. (2018). “Capturing the Sounds of an Urban Greenspace”. In International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XLII-4-W11, pp. 19–26. Copernicus GmbH.

Exploring the data

The audio data files are large in size and long in duration. 10-second samples at 192kHz are 3.5MB in size and and each ACD generates 1.26GB every 6 hours. It is difficult for humans to listen to these files. All of the sounds are scrambled below 7kHz to obscure human voice which makes the sound inherently noisy and disorienting. To spot trends and shifts over long periods of time requires an attentive form of listening that is also very difficult and time consuming.

We have developed an experimental application that allowed us to extract the spectral energy across each 10-second segment and save these aggregated snapshots of spectra alongside one another. With this application, is possible to rapidly ‘scrub’ through the spectral content but still use our ears to pick out areas of interest very quickly. When a spectral snapshot seems interesting or surprising, we can listen to the original sound file that made the spectra.

Another approach we have explored involves concatenating the files into 6-hour chunks and generating spectrograms of that entire period of time, as shown in the following figure [click image to expand]:

Spectrogram spanning six hours of data from 12.00 am to 6.00 am on the 13th June 2018 from ACD3. Towards the righthand side of the image, an increase in spectral activity is noticeable. This correlates to what we would expect around 4.00 am on the morning in question — dawn was 3:56am in Edinburgh that day.

Long-duration spectrograms like this give an instant overview of a period that a researcher may find interesting. Whole days and different ACDs can quickly be compared while trends, anomalies and other features (such as sounds in the ultrasonic band) noticed at a glance. Researchers interested to explore more closely can then home in on these specific files and generate further close-up spectrograms of particular areas of interest. With several of these images lined up researchers can look longitudinally across the season or seasons, laterally across the day and spatially across however many boxes are making recordings.

Reflections on Outreach

A key part of our approach to CitySounds was involving the most relevant stakeholders from the outset. This included

  • soliciting their input to the initial experiment proposal;
  • inviting a broad spectrum of people onto our management team;
  • inviting an even wider group to our initial Co-design Workshop, in order to plan how to create engagement and impact around the project.

While it is not always easy to get a community gardener, a senior data technologist, a Council biodiversity officer and a sound designer talking to each other, it worked amazingly well in this experiment. The ‘kick-off’ and ‘touch-down’ (closing) Management Meetings as well as the Co-design Workshop provoked insightful, valuable and engaging discussions where knowledge, learning and ideas were shared across research disciplines and city sectors. We formed new relationships and are continuing to build on them. One outcome was that a conversation in the Co-design Workshop led to a team of people submitting a proposal to Nesta extend the project to three more parks in Edinburgh, and we are very happy to say that project is now going ahead.

The more challenging part of the project was developing relationships with people who live in and around the Meadows and attracting them to our workshops. We had a very high response to the talk from Chris Watson and the Sonikebana event because it was publicised through a partner organisation — New Media Scotland — that had a large, established, active and interested community. Reaching out to community groups, Community Councils, and local residents requires working through multiple channels and building up relationships over time. While we worked as much as possible through the contacts and networks of the team members, it was challenging to attract community biodiversity enthusiasts and greenspace users to our workshops. Valuable insights from the final management team meeting were that (a) we should take our message out to community groups where they are already meeting, inform them about the project and build a relationship with them first, if we hope to get them to attend workshops; and (b) we will attract a lot more interest in the project once we have a larger volume of data from the devices in a form that can be easily shared.

This experiment also helped us to reflect on what we mean by ‘community’ and ‘citizen’ and how we engage with and reach people with new ideas and opportunities at the interface of technology and civic/city issues. We aimed to reach biodiversity enthusiasts with new monitoring technology, data and communication methods; technology enthusiasts with sound recording devices and biodiversity data; and sound art enthusiasts with audio and biodiversity data, but also people using or interacting with the Meadows who might have little or no experience of biodiversity monitoring, sound recording devices or biodiversity and audio data analysis and presentation. All of these people are in some way community members and citizens of Edinburgh, but the latter group was our ideal target and was, unsurprisingly, the most difficult to identify, reach out to, and draw in.

As we further develop the Edinburgh IoT network, we will be continuing our outreach activities and continuing to build relationships with people and groups interested in biodiversity monitoring. We will also continue collecting and using audio data to improve the ways that we interact with and value greenspace and the natural environment in the city. Finally, we will alo be looking at ways that we can connect with and support community initiatives that are already underway and have strong and active groups around them. One example would be the Fountainbridge Canalside Initiative ‘Living Wild’ project, which is developing a community plan for greenspace within a major city development.

In summary, CitySounds was an excellent opportunity to begin community engagement with Edinburgh’s new IoT initiative, which is being designed as a Research and Innovation Service for experimenters. We think that it is absolutely essential for citizens to be involved in experimenting with tools, services, data and urban development. It is part of the explicit mission of key partners in this project, including the Edinburgh Living Lab and Edinburgh Living Landscapes, as well as of the Scottish Government, to ensure that citizens are actively involved in shaping the way the city develops, including the ways that technologies and data are used to understand, inform and communicate about city decision-making

First outing for Sonikebana v1

Upstairs in St Cecilia’s concert hall are six boxes on wheels. Each box contains a small computer, amplifier, speakers, battery and a compass sensor. Playing through these boxes are sounds recorded in and around the Meadows in Edinburgh. As you move the boxes around, the sound changes. When you’ve discovered positions that you think you like, sit back, lie down, relax and wait for others to shift things. If you want to make a change, intervene…

Download (PDF, Unknown)

Close up of laser etching on speaker casing

Chris Watson: Inside the Circle of Fire

On 5th April, field recordist and sound artist Chris Watson helped set the CitySounds project into a wider context by presenting recordings from his sound installation Inside the circle of fire: A Sheffield Sound Map. Before a large audience in the Reid Concert Hall, Chris guided us through a project that describes the sound world of the city of his birth in dynamic multichannel sound.

Audience at Reid Concert Hall, University of Edinburgh

As Chris said: “We tend to hear everything, but we rarely listen. We live in such a noise-polluted environment.” The event was a great opportunity to focus attention on the richness of urban sounds rather than ignoring them.

CitySounds Makes a Noise

We are lining up a number of exciting events to round off the current phase of CitySounds. Check out the details below.

Thursday 5th April, Talk by Chris Watson

3:00 pm – 4:30 pm, Thursday 5th April, Reid Concert Hall, Bristo Square

We are holding a presentation featuring guest speaker Chris Watson. Chris is a field recordist and sound artist, and will reveal sounds from his sound installation Inside the Circle of Fire: A Sheffield Sound Map, a project that describes the sound world of the city of his birth in dynamic multichannel sound.

Registration (waitlist only) and more information here:

Thursday 5th April, sonikebana v1

5:00 pm – 7:00 pm, Thursday 5th April and 2:00 pm – 5:00 pm Friday 6th April, St Cecilia’s Hall, 50 Niddry Street
Sound artist and composer Martin Parker has been listening to material recorded by Edinburgh’s CitySounds project and has been recording audio from the Meadows himself. He has placed some of these sounds inside custom-built portable loudspeakers. At this installation, visitors are invited to move the loudspeakers around the space in order to design and reorganise the soundscape as they hear-fit. The sounds playing are not fixed but actually morph-based on the direction that the speakers face — every change in position of the speaker will change the sounds you hear. Think of it as a kind of audible flower arranging.

Registration and more information here:

Friday 5th April, sonikebana v2

2:00 pm – 5:00 pm Friday 6th April, St Cecilia’s Hall, 50 Niddry Street
Sonikebana installation open to the public.

Friday 6th April, Zoë Irvine Workshop, Sensing Information from Sound

4:00 pm – 7:00 pm Friday 6th April, starting at St Cecilia’s Hall, 50 Niddry Street

Zoë Irvine is an artist working with sound, exploring voice, field recording and the relationship between sound and image. Join Zoë for a listening and recording sound walk around Edinburgh’s heartland. Rather than listening out for the usual ghouls, you’ll be listening for the noises made by people, their machines and the environmental sounds of nature too. You’ll then explore ways of revealing information about the soundscape and what everyone and everything is doing within it.

Registration (waitlist only) and more information here:

CitySounds Public Workshop 1

The CitySounds project held two workshops on 19 February 2018, with special guest Kate Jones from University College London. The ideas for the workshops were conceived at our co-design workshop earlier this year.

Two aims that we identified for the community workshops were a) to find out what people might want to learn about nature and biodiversity in the city through sound (as well as potentially other forms of environmental monitoring and data collection) and b) to demonstrate how and what we can learn through the initial sound recordings coming from the project’s Audio Capture Devices and perhaps teach some basic skills in audio data analysis.

Our first workshop took place in the afternoon at the University of Edinburgh Informatics Forum. We had special guest Kate Jones from University College London, who presented an excellent example of learning about nature in the city through sounds — the Nature-Smart Cities project. The project brings together environmental researchers and technologists to develop the world’s first end-to-end open source system for monitoring bats, to be deployed and tested in the Queen Elizabeth Olympic Park, east London.

Kate gave a fantastic presentation about the project, starting with the foundation of monitoring biodiversity. How might we track biodiversity in urban areas and understand its role in helping us to live safely, productively and healthily? She encouraged us to imagine the Biodiversity version of ‘Industry 4.0’ — how could cyber-physical systems, Internet of Things, networks, data-driven and adaptive decision-making machines be employed to support biodiversity conservation and help stop the rapid loss of biodiversity across the planet?

Kate Jones describes data processing pipeline for bat monitors

Kate and her team developed the Echo Box, which is essentially a Shazam for bats. It picks up the frequencies that bats communicate with and uses an algorithm to identify the call and provide an indication of which species has been heard. It then sends the information back to a central server and displays the information online at Fifteen Echo Boxes are installed on lamp posts around Queen Elizabeth Olympic Park and have been continuously monitoring bats for three months.

Olympic Park Echo Box

While the original idea for the project came from Kate’s passion for biodiversity conservation, as other people found out about the publicly-available data, they generated their own ideas from it. A group of students built an arcade machine based on the data that has become a highlight at the visitor centre, while researchers added bat data to a 3D augmented reality visualisation of park. Another group devised small 3D-printed gnomes placed around the park that people could interact with via a chatbot to find out more about bats in the park.
‘Memory Gnome’ from Olympic Park

We were all thoroughly inspired by the incredible amount of work that went into the project and the possibilities for learning about nature through sound while also engaging a wider population with biodiversity in the city.

Simon Chapple then shared the vision for the CitySounds project and encouraged us to begin imagining all the things that we could learn through audio data. Smart sensors can recognise what is taking place in the environment, and an array of multiple sensors can work out spatially where a sound comes from. In a particular area, audio data can allow us to identify species of birds present, bat activity, volume of traffic, car accidents and more – and a wide spectrum microphone can even allow us to record mice screaming at each other!

Following Simon, Jonathan Silvertown sparked our imaginations to the possibilities of all the different creatures that are roaming around our cities and that we could potentially learn about through IoT and other technologically-advanced forms of biodiversity monitoring. He showed us the National Biodiversity Network’s Atlas of Scotland, which keeps a record of all the creatures that have been recorded in a particular area. So, from where we were in the Informatics Forum in the centre of the city, this is what we might find:

Screenshot of interactive map from NBN Atlas Scotland

We hope that the CitySounds project will provide not only a replicable method for learning about nature through sound but also a specific insight into the Edinburgh soundscape, from nature (weather, animals, birds, insects, bats), activities (walking, cycling, playing sport, festivities), transport (traffic, car horns, trains, planes), machines, electrical and electronic devices, breaking glass, noise pollution) through to the one o’clock gun, the many incidents of fireworks and the festivals large and small that take place around the city throughout the year.

Collaborative box building

Come and help us build some wooden tree boxes, which will be installed around the Meadows with microphones inside them for the CitySounds project. This will be a great chance to learn some basic woodwork skills, whilst also contributing to an exciting community project. No previous woodwork experience required!

Please register using this Eventbrite link.