One night last winter, I heard a Great Horned Owl, grabbed my recording equipment, and ran to the back porch. Two owls in my yard were hooting back and forth; a second pair off to the west answered. My yard must be on the border between two territories.
I’ve never before heard four owls hooting simultaneously, but my recording was awful. In the four decades we’ve lived in our quiet residential neighborhood in Duluth, Minnesota, background noise has melted from my consciousness even as it’s grown louder. A quarter mile to the north and south are avenues with steady traffic; a snowmobile trail runs beyond one. My microphone picked up trucks and a snowmobile, overwhelming the owls’ hoots. Gas furnaces, barking dogs, two airplanes flying over, cars starting up, doors slamming — ordinary sounds of human life muddied the owl recording beyond repair.
Want to learn more about birds? Sign up for our newsletter, full of birding tips, news, and more!
My neighborhood is quiet by urban standards, but much remoter places are also noisy. My mother-in-law lived in rural Wisconsin, half a mile from her nearest neighbor and a highway, and a mile from Lake Superior, yet virtually all my recordings from her place include traffic and motorboat or snowmobile noise.
We unconsciously filter out most background noise from our daily soundtrack. I notice sirens in my neighborhood but filter them out in Chicago or New York. Some everyday sounds are too loud to filter out. I grew up on a flight path near O’Hare Airport. When a jet approached, without even thinking about it we stopped talking mid-sentence, picking up after the jet passed.
Birds compensate for background noise, too. In 2017, researchers from George Mason University found that in three urban parks in greater Washington D.C., Eastern Wood-Pewees produced songs shorter and of a narrower range of frequencies than normal to be heard above loud traffic noise. Pewees there have declined by 50 percent in recent decades, and noise may be a factor; females seem to prefer mates who sing normal songs. During 36-hour weekend road closures, the study birds produced more natural songs. Perhaps temporary road closures could benefit urban songbirds that adjust their songs for fluctuating traffic noise levels.
Areas with no human-produced noise are growing harder to find, but a project called “One Square Inch” is trying to make people more aware of how noisy our world has become and how important and restorative a truly natural soundscape is. The organizers marked off 1 square inch in the Hoh Rain Forest of Olympic National Park, 3.2 miles from the visitor center above Mt. Tom Creek Meadows on the Hoh River Trail, as “one square inch of silence,” its soundscape entirely natural. This may be the quietest place in the lower 48 states in terms of human-generated sounds.
“Silence is not the absence of something,” says founder Gordon Hempton, “but the presence of everything.” Being able to record the nuances of four Great Horned Owls hooting on a winter night would have meant everything to me.