Aldo Leopold’s Field Notes Score a Lost “Soundscape”

Among his many qualities, the pioneering wildlife ecologist Aldo Leopold was a meticulous taker of field notes.

Rising before daylight and perched on a bench at his Sauk County Shack in Depression-era Wisconsin, Leopold routinely took notes on the dawn chorus of birds. Beginning with the first pre-dawn calls of the indigo bunting or robin, Leopold would jot down in tidy script the bird songs he heard, when he heard them, and details such as the light level when they first sang. He also mapped the territories of the birds near his shack, so he knew where the songs originated.

Lacking a tape recorder, the detailed written record was the best the iconic naturalist could do.

“Leopold took amazing field notes,” says Stan Temple, a University of Wisconsin–Madison emeritus professor of wildlife ecology and now a senior fellow of the Aldo Leopold Foundation. “He recorded his observations of nature in great detail.”

Using those notes, Temple and Christopher Bocast, a UW–Madison Nelson Institute graduate student and acoustic ecologist, have recreated a “soundscape” from Leopold’s 70-year-old notes. But the dawn chorus that Leopold heard in 1940 no longer exists at the shack, Temple explains. The mix of species today is different due to changes in the landscape and changes in the bird community around the Shack.

More noticeable is the thrum of the nearby interstate highway, audible at every hour from Leopold’s storied sanctuary, and the other constant and varied noises of the human animal. Since Leopold’s time, for example, the internal combustion engine has roared to soundscape dominance, whether as an airplane overhead, a rumbling motorcycle, a whining chainsaw or an outboard churning on the nearby Wisconsin River. “The difference between 1940 and 2012 is overwhelmingly the anthrophony – human-generated noise,” explains Temple. “That’s the big change. In Leopold’s day there was much less of that.”