Sonifying the wolves and moose of Isle Royale: transforming data into music

Wolf

Moose

Climate

What am I experiencing?

An example of a rare and special art form called data-driven music or sonification. Imagine an orchestra of instruments. In this orchestra, the musicians playing the instruments are not human. Rather the instruments are played by data – data that has been collected from nature. In this particular case, the music is created by numbers representing fluctuations in wolf abundance, moose abundance, and climate on Isle Royale National Park over the past five decades (1959-2014). The documentation of those fluctuations represents the longest continuous study of any predator-prey system in the world. Click here for details on that ecological research.

More specifically, you are experiencing fluctuations in wolf abundance over the years as musical notes that seem to be rising from a dulcimer-like instrument. And, you hear fluctuations in moose abundance as notes flowing from a pulsing rhythmic synthesizer. Variation in weather from year to year – temperature and precipitation – are registered as varying velocities of rain and other musical notes. The music contains other creative features. For example, wolf abundance is also accented by actual wolf sound effects. Also, listen for changes in the amount of reverberation in the wolf track. That reverberation follows temporal trends in the level of inbreeding that the wolf population has suffered over the years. Other ecological phenomena, such as predation rate and calf production, are also represented by various harmonic and textural elements.

This sonification of Isle Royale wolves and moose involves two basic components. The first is technically demanding and requires transforming numbers into music with mathematical techniques, including Fourier transformations. The second component is artistically demanding and requires a specific translation from numbers to music that is not only faithful to the numbers, but also pleasing to the ear.

You can learn more about music composed by nature in John Luther Adams’ book, entitled “The Place Where You Go to Listen: In Search of an Ecology of Music.”

What are those black boxes with the orange traces?

Those are spectrograms – a means for visualizing sound. In a spectrogram, time is metered out across from left to right. The energy (or volume) of a sound is indicated by the brightness of the orange coloring. The frequency (or pitch) of a sound is indicated by the location (up or down) on the spectrogram. That is, higher pitches are toward to top and lower pitches are toward the bottom of a spectrogram. Most complex sounds are the combined sound of many frequencies all heard at the same time.

To help build your intuitions about interpreting a spectrogram, spend a moment with each of the several spectrograms just below.

  1. A human saying, “Ta ta ta” [1]:

ile:Praat-spectrogram-tatata.png

Because the lower frequencies are most dominant (i.e., darker traces toward the bottom) you will not be surprised to learn that this is a male voice.

  1. And now a more complicated sound, that of a human saying, “nineteenth century” [1]:

https://upload.wikimedia.org/wikipedia/commons/c/c5/Spectrogram-19thC.png

You can identify the five syllables in that phrase. An expert in reading spectrograms would be able to identify the phrase without being told the phrase.

3) The spectrogram of a lone wolf howling [2]:

 

4) A group of wolves howling [3]:

 

5) Spectrograms are a basic tool for a small group of scientists studying the field of acoustic ecology. Just a few notes from their long song of insights:

⇒ Birds sing in higher pitches when they are singing in the presence of urban noise [4].

⇒ An elephant living in dense jungle can communicate to another from more than a mile away using ultrasonic sounds that are deeper than the deepest organ pipe and deeper than any human can hear. Some of these sounds are transmitted as vibrations through the ground. Elephants hear these sounds with their feet.

⇒ Male crickets announce their sexual desire by rubbing their serrated leg against a wing vein. We hear the resulting vibration as a cricket chirp. Female crickets respond to amorous announcements made by males of their species, but not males of other cricket species. An individual chirp – that is, a single rub of the leg – produces essentially the same pitched sound, regardless of the cricket species. But some species chirp faster and others slower. As to not rendezvous with a male of the wrong species, female crickets can tell the difference between, for example, 43 and 51 chirps per second, a difference of just eight rubs of the leg per second [5].

⇒ Whale sounds have such a perspicuous structure – notes nested within phrases, phrases embedded into themes, and themes arranged to make a song. Yes, whale sounds are songs in the truest sense of what a song is. A whale song’s syntactic structure has complexity far exceeding that of any bird, and is second only to human songs. Whale songs also evolve over long periods of time (months and years). Whales living in one part of the world’s oceans tend to sing the same song, while whales living elsewhere sing different songs. Whales sometimes stop singing or leave parts of the ocean that are polluted by the sound of ships’ engines and propellers [6].

Since you have whale songs on the mind, here is a spectrogram of approximately 8 minutes of whale song [7]:

 
  1. Finally, here is a screen capture from the moose track of the Isle Royale wolf-moose sonification:

Notice any similarities to the fluctuations in abundance of Isle Royale moose (black line below)?

Sources:

[1] "Spectrogram." Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 

[2] Freesound.org, Freesound team, Universitat Pompeu Fabra, Barcelona Spain, www.freesound.org/people/viorelvio/sounds/66258/

[3] Freesound.org, Freesound team, Universitat Pompeu Fabra, Barcelona Spain, www.freesound.org/people/Paresh/sounds/158780/

[4] Slabbekoorn H & M Peet. 2003. Ecology: Birds sing at a higher pitch in urban noise. Nature, 424(6946), 267-267.

[5] Joyce, C and B McQuay. 2015. Good vibrations key to insect communication. National Public Radio. August 27th, 2015 (featuring the research of Laurel Symes).

[6] B McQuay and C Joyce. 2015. It took a musician's ear to decode the complex song in whale calls. National Public Radio. August 6th, 2015, and B McQuay and C Joyce. 2015. Listening to whale migration reveals a sea of noise pollution, too. National Public Radio. August 13th, 2015 (featuring the research of Roger and Katy Payne and Christopher Clark).

[7] Freesound.org, Freesound team, Universitat Pompeu Fabra, Barcelona Spain, www.freesound.org/people/listeningtowhales/sounds/323048/

 
 

Who Created This?

This experience was created by four artists, Paul Kirby, Thomas Conran, Collin Doerr-Newton, and Mason Pew.  They created this experience for you as a senior project while students at Michigan Technological University. Matt Vaught was instrumental in bringing this sonification to you as an interactive webpage. Their efforts were guided by Christopher Plummer from the Visual and Performing Arts at Michigan Tech.  Below is a short statement from two of the artists.  

“Transforming the wolf data into perceptible sounds drove us deep into ecology of Isle Royale wolves. We had an overwhelming about of information available to us, but what struck me most was the important influence that inbreeding has had on the wolf population. Here in this sonification, increases in inbreeding are represented in increases in the amount of reverberation in the wolf track. When we embarked on this project, we hoped to create a truly thought provoking experience. Yet we did not anticipate how the project might transform us. We had all been familiar with the science of wolves and moose on Isle Royale, but this unique opportunity allows us to experience and interpret the wolf and moose of Isle Royale through the lens of art.” 

Thomas Conran

“To widen our soundscape, we included climatological data which ebbs and flows over the years. Doing so provided a rich environment from which the wolf and moose soundscape could rise. We focused on the most basic elements of climate – temperature and precipitation. As precipitation increases so to does the volume of the rain sample. The temperature data controls a synthesizer pad, which increases in pitch with increasing temperature. I can say with complete honesty that I had an absolute blast working on this project with my colleagues and digging into such a truly interesting study. It has been a privilege to partner with John and Rolf, who graciously supported this project from its inception.”

Mason Pew

How to interact with this experience?

You can control the relative volume of each track (wolf, moose, and climate) with the slider bars inside each spectrogram. Take a moment to focus on each track, one at a time.

A richer way to interact with this experience begins with a thought from neuroscientist, Seth Horowitz [1]:

"You hear anywhere from 20 to 100 times faster than you see, so that everything that you perceive with your ears is coloring every other perception you have and every conscious thought you have. Sound gets in so fast that it modifies all other input and sets the stage for it."

Sound and music also have a powerful capacity to trigger our emotions – peace, anxiety, joy, fear, excitement, love – emotions that shape the quality of our lives [2]. Our emotional response to a sound is partly universal. People from different cultures and experiences tend to respond to particular sounds with similar emotions. Your emotional response to a sound is also personal – for any particular sound there is considerable variation in one’s emotional response [3]. And, we can condition ourselves to respond to sounds in certain ways, but only if we are attentive to that sound-emotion connection in the first place.    

Alas. We are primates. As primates we are endowed with an exquisite sense of sight – taken to be the primary source of input about the world around us. Our vision is so exquisite and so informative that we lose sight of the sounds and their influence on our bodies – sounds in which we are forever and inescapably bathed. While you can close your eyes, you cannot so easily shut out the sounds of the world.

The richest use of this sonified wolf-moose experience is as an opportunity to practice listening. Take a moment. Take a breath. And, listen. Close your eyes. And, listen. Listen to the overall sound of the music. Listen to the other sounds that compete with the music – hum of a refrigerator or the sound of traffic. Listen deeply. Probe the layers, listen to a subtler layer that is easily overlooked (Good Lord!) on a first listening.

Listen to the music and listen to your body’s response.

 

Sources:

[1] Montange, R. 2015. How Sound shaped the evolution of your brain. National Public Radio. September 10, 2015.

[2] More about the sound-emotion connection is found in The Universal Sense: How Hearing Shapes the Mind by Seth Horowitz (2013).

[3] Ericson, J. 2013. Fundamental link between emotions and sound perception identified in new study. Medical Daily. Jun 30, 2013. See also, this link.

 

What are scientists and artists saying?

“Numbers and feelings, facts and emotions, the measurable and the immeasurable. Art and science are the only two vehicles for knowing nature. We work so hard, and lose so much, divorcing science and art. But not here, not in this commingling of science, art, and nature.”

  • John Vucetich, Ecologist, Co-leader of the Isle Royale Wolf-Moose Project