When nature calls, just listen.

When Bernie Krause treks out into the Costa Rican rainforest he is surrounded with music – by bass players, by flutists, by drummers, and high pitch falsettos.

This music follows him everywhere – to the Great Barrier Reef and Grand Teton National Park But the musicians aren’t people – they’re animals and they make up a constant symphony of creatures that surround us even though we may not hear it. Krause and a few others have made it their life goal to document and share this beautiful and endangered sound in order to protect it.

The soundscape in the rainforest has changed over the years.

Krause is a bioacoustician, a soundscape ecologist, and a professional listener of sorts.

He has produced over 4,500 hours of soundscapes in different rainforests and coral reefs. But he says fifty percent of the habitats he has recorded are now quiet.

“While a picture may be worth a thousand words, a soundscape is worth a thousand pictures,” he says.

In his book, the Great Animal Orchestra, Krause explains the elements of biophony and the components of a soundscape. Biophony, he describes simply, is “the sound of all living organisms except us.” They are the “voices of the whole ecological system.” And like any sound, music from animals has frequency timbre, tone, amplitude and envelope, which can be charted after its captured with   professional recording equipment.

Bernie Krause describes biophony in his new book, The Great Animal Orchestra.

According to Krause, A soundscape contains three basic sources: the geophony, which includes all nonbiological natural sounds like wind or ocean waves; the biophony, which embraces the biological, wild, nonhuman sounds that emanate from environments; and the anthrophony — man-made sounds, commonly referred to as noise.

Krause got his start in music. He played with the folk band The Weavers in the 60s, dabbled in electronic music and popularized the electronic synthesizer. Before switching to acoustic ecology, Krause started out marketing his recordings as music, on LPS and CDS (and he still considers them to be musical). But there’s also an ecological purpose to soundscape recording.

When scientists study our natural environment, they usually chart visible and physical data i.e. water levels, the number of species in a given area, temperature, or erosion. However, biophony suggests that the data we can hear – the sounds of our habitat – are just as important as our visible habitat.

When Krause records a forest, before and after environmentally sensitive, “selective” logging, the forest may appear unchanged to the eye, but the soundscape is devastated. The ear is true and the true damage can only be heard.

Because animal sounds differ depending on seasons, temperatures, mating habits – a soundscape ecologist’s hypothesis is that the more “musical” the creatures are, the healthier their environment is.

Krause has recorded the soundscapes of rain forests in Costa Rica, Coral Reefs in Australia, and California’s Lincoln Meadow at the same date, multiple decades apart, to record the sounds of the habitat to see what’s changed. The differences between the soundscapes are outstanding. You can hear the effects of climate change, logging, and endangered species.

But hearing and recording soundscapes aren’t just for acoustic ecologists, soundscape artists, and radio professionals.

“I view soundscape ecology as the first form of citizen science, and I can assure you there are tons of soundscape mapping projects popping up around the world,” says Gordon Hempton, a soundscape ecologist based out of Washington State.

Catalyst  tries its hand at recording soundscapes by the Ottawa river.

The first step is learning to listen to what’s around us instead of just “hearing,” says Krause.

With the advent of new digital recording technologies that are easy to use, light in weight, small in size, and financially accessible to a wide range of people for under $200USD, lots of people, at all ages, are becoming more aware of their acoustic surroundings, adds Krause, who belongs to a worldwide field recording chat room.

“5 or 6 years ago it had around 100 members. Now, it’s expanded to over 2000. And each of those participants, from newbies to professionals could be considered citizen scientists since they all contribute in some way to the wealth of knowledge.”

His advice on where to go first? “If we want to hear the environment, particularly the natural kind, we have to find places where there is little or no human noise, and simply shut the hell up. The French language expresses it perfectly in one word: Ecoute!”

And as Hempton warns, there will be fewer and fewer quiet places on earth if we don’t start simply listening.