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The Niche Hypothesis: Creature Vocalizations and the Relationship between Natural Sound and Music
by Bernard L. Krause, Ph.D.

Prior to European migration to North America, Native Americans experienced their aural world as a symphony of natural sound, where all creature voices performed as an integral part of an animal orchestra. Today, with their habitats radically transformed, and with tribes displaced, many Native Americans have lost contact with their source of natural sonic textures. Along with this loss, Native American music has tended to lose its link to the natural world. Fortunately, in some isolated corners of our planet, this fragile link continues to exists. Some older, forest-dwelling societies remain keenly aware of the impact of natural sound on the totality of their lives. They integrate natural sound into nearly all spiritual and practical aspects of their existence.

As an artist and naturalist, I long have been intrigued by the ways in which night hunters from non-industrial societies can determine, through sound alone, the types, numbers, and condition of creatures hundreds of meters distant in the dark. I also have been astounded by the ability of these hunters to determine exactly their bearing in a darkened forest, simply by listening to surrounding sounds. To the untrained Western ear, nothing appears especially distinct. To them, the subtle sounds can be read like a book. I also marvel at how closely the music of these peoples reflects the complex rhythms, polyphonies, and sonic textures of the habitats in which they live. In contrast with the sonic sophistication of these peoples, we primarily live in a visual culture. We no longer connect spiritually, aesthetically, or practically, to everything our natural surroundings, the "wild natural," can tell us through sound. This loss of sensitivity to natural aural messages has tended to distort our view of the natural world.

For me, some insight into our ancient aural past began some 30 years ago. I was then working with the Nez Perce in Idaho and central Washington, recording their music, oral histories, and the sounds of their natural environment. One afternoon I interviewed a tribal elder named Angus Wilson, and shared with him many familial and personal revelations. When I told him I was a musician, Angus suddenly became quiet and pensive. "You white folks know nothing about music," he blurted out, half serious, half teasing, but with a confrontation unusual for his culture, "but I teach you something about it if you want." I had been offered a chance to learn. I could not turn down his offer.

Early the next morning we drove to Lake Wallowa, in northwestern Oregon, where Chief Joseph and his small band of Nez Perce once had lived, hunted, and fought bravely before their eventual capture and banishment by American frontier armies. Angus led us to the bank of a small stream flowing into Lake Wallowa, and motioned us to separate and sit quietly. As time went by, staying warm in the chill October air became a challenge.

Occasional glances 50 feet upstream, however, found Angus sitting stoic and motionless. For almost an hour, the only sounds were those of jays, ravens, and the flowing stream. Then suddenly a slight breeze came up the valley, stirring the branches of aspen and fir trees. From nowhere, the whole forest burst into a cathedral of sound! Like a huge pipe-organ with all its stops out, a cacophonous chord echoed from everywhere in the valley. Angus saw the startled look on our faces, and walked slowly toward us. "Do you know what makes the sound?" he asked. "No," I answered, shivering as I spoke, "I haven't the slightest idea."

Without a word, Angus walked over to the stream bank, and pointed to reeds of different lengths, broken by wind and newly formed ice. Removing his hunting knife, Angus cut a reed at water line, whittled some holes, and, without tuning, began playing a melody with his newly-created instrument. After a long while he stopped, and with quiet assurance said "This is how we learn our music." Ten years later, while recording in eastern Kenya, memories of lessons learned on a frosty October morning near Lake Wallowa returned. Music exists within, and is derived from, nature. I had been recording for long hours, over many evenings, waiting for some grazing elephants to stop pulling up trees around my camp, and to render some significant elephant sounds. Exhausted from heat and lack of sleep, I began to experience the ambient chorus of singing insects, and the cries of distant hyenas, as a kind of animal symphony. Many thoughts occurred to me as the puzzle of what I was hearing began to coalesce into clearer patterns. I gradually became convinced that my wilderness symphony might not be an illusion, the product of over-stressed imagination. I began recording the ambience. In the light of day, and with clearer mind, would I feel the same in hearing my creature symphony replayed? Indeed, my concept of a natural symphony has clarified over time.

All animal species have evolved to fill eco-niches which adequately allow for their food, shelter, physiological, and other life needs. At the same time, these eco-niches accommodate restrictions imposed by the species' living and non-living environments. Similarly, sound producing organisms appear to have evolved to fill acoustic niches which (continued page 7) allow for their communication needs. Likewise, these acoustic niches accommodate sonic restrictions imposed by the species' living and non-living environments. These acoustic niches, within a community of sound-producing organisms, are measurable through parameters which include frequency, amplitude, timbre, duration of sound, and diurnal and seasonal timing.

Figures 1 and 2 illustrate one aspect of separation of sonic niches in respectively simple and complex sonic environments. This aspect is interspecies frequency avoidance. Horizontal dark lines in Fig. 1 show a unique mixture of insect sounds, recorded in the Virgin Islands, which occupy several frequency bands between 20 and 10,000 Hertz. The short lines toward the bottom represent the low voice of a Zenaida Dove (Zenaida macroura). Its plaintive call avoids frequency interference with the insects. In Fig. 2, recorded in Borneo, horizontal dark lines also represent ambient insect sounds, but these occupy a broader range of frequency bands between 20 and 20,000 Hertz in a more complex environment. Here the Paradise Flycatcher (Ter psiphone paradisi) delivers a song made up of three harmonic components, called formants. As with the Zenaida Dove, the Paradise Flycatcher manages to avoid frequency interference with the insect chorus, even though the insects resonate over a very broad frequency range. In a similar way, in all unaltered habitats in which I have recorded, birds, mammals, and amphibians display vocalizations which tend to avoid frequency interference with less mobile, more ubiquitous creatures, such as insects.

Additional to a need for frequency avoidance with co-existing animals, several other selective forces have acted to shape animal sounds, and to define acoustical niches. One such force is the vegetative and physical environment in which an animal lives and vocalizes. Scientists have discovered, for example, that animals living close to the ground, and having to communicate through thick brush, often have songs or calls of low frequency and/or sharply defined notes. These songs or calls travel better through undergrowth. Animals living high in trees, and/or in more open environments, often have high-pitched, buzzy voices, with individual notes less well defined. Their songs or calls better suit communication needs where sound travels unimpeded. Yet another selective force shaping an animal's song or call is the distance over which the animal must vocalize. Elephants, which often must communicate over great distances, use long-distance calls that resonate in subsonic frequencies. Mice, on the other hand, communicate over short distances with high-pitched squeaks. Some other selective forces which have acted, over evolutionary time, to shape creature vocalizations are the time day or time of year communication is needed, and the relative need for messages carrying different meanings.

Healthy natural environments worldwide tend to have a full contingent of sound-producing animal species. Available acoustical niches are occupied by sonically compatible species. Non-healthy environments tend to be sonically depauperate, and available acoustical niches can be empty, or be occupied by alien species that compete acoustically with native species. The study of acoustical ecology, the holistic study of sounds in natural environments, began in the late '70s with Dr. Murray Schafer and Barry Truax. Among other values, acoustical ecology can aid in evaluating the health and biological integrity of both marine and terrestrial habitats.

Acoustical ecology presents a creature picture far different from that gained through studying individual animal sounds. While single-species acoustical research continues to answer some types of scientific questions, in my opinion there has been overemphasis on these types of studies. I believe there has to be greater understanding of how all animate and inanimate sounds integrate within natural environments. Not the least of reasons for this is that a more holistic approach can help us rediscover our cultural link to the sounds of the wild natural, before it disappears.

Non-industrial peoples living in undisturbed habitats have grown up with implicit knowledge of acoustical niches, and of an ambient sonic framework to their natural environment. They have used this knowledge in their everyday living and survival. My enlightenment came through a different route. In field recording, we typically spend about 500 hours of field time to obtain just 15 minutes of premium, usable material. Among other things, tremendous amounts of recording time are lost to the sounds of distant chain saws, overpassing aircraft, or slow-plying riverboats. Following my experience in Kenya, I have taken more and more to recording ambient sound during these sonic down times. This is partially because there often is little else to do, and partially because I am curious about what surrounding nature sounds like when there is no particular aural focus.

What has emerged for me, in examining ambient recordings from many worldwide habitats, is an understanding that nature tends to produce "biophonies" of ambient sound. This is not unlike a modern symphony, in that different animal sounds, like different symphonic instruments, tend to make an unimpeded and complementary contribution to a larger whole. Furthermore, just as some instruments may drop out of a symphony, to be replaced by others, so some animal species will sequentially replace others in a biophony. Most importantly, however, biophonies from different territories tend to be unique. As one moves through a rain forest, for example, a changing mix of animal sound can produce an animal vox unique to each particular section of (continued page 10) the forest. This occurs even when vegetation and geological features appear similar. Thus, areas of the forest may better be defined by their unique ambient sound, than by anything obviously visual.

A concept of biophonies has further matured, for me, into a hypothesis that the roots of ancient musical composition were derived from an implicit understanding of biophonies by pre-industrial peoples. From the animate and inanimate sounds of their natural environment, these peoples developed some pretty complex musical formulae. One only needs to hear the compelling music of the Bayaka of Central Africa (Louis Sarno, Ellipsis Arts, 1996), or of the Amazonian Jivaro, to recognize the musical connections these peoples have with their acoustic environment. In turn, modern musicology and musical instrumentation have evolved, over the ages, from the musical understanding and creativity of similar "children of the wild natural," tribes long since gone, and long since forgotten.

As modern industrial humans, we have become philosophically and experientially separated from our natural surroundings. For many, this separation is greatest with respect to natural sounds. To hear things in nature we must stop, let time stand still, and listen. Few of us take the time.

By learning to listen to wildness, and to appreciate its incredible beauty, we yet may be able to mitigate a deafness to our lovely world. Natural orchestrations, the sounds of unaltered temperate, tropical, polar, desert, and marine habitats, are becoming increasingly rare and difficult to find. Yet the biophonies of these endangered habitats may hold keys to our musical past. This was a lesson I learned from the late Angus Wilson, playing a whittled reed flute beside a muted mountain stream, on a frosty cold autumn morning in the Oregon wilderness, many years ago.

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