For the Sake of the Birds, We Humans Need to Keep Our Voices Down
In urban areas all our human noise is making it difficult for some birds the hear one another, and find mates.
At their best, urban areas can harbor an astonishing variety of bird species, with parks both large and small providing critical habitat for migratory birds (think New York's Central Park and all the birds that pass through it). But urban areas can also be quite noisy, and birds aren't always keen on noise. In fact, it could be driving down bird diversity in urban areas, as new research published in Global Change Biology shows.
It seems that our noise doesn't just bother us (or even kill us, slowly), it can really bother birds as well—particularly species whose songs are composed of low frequency sounds. Looking at birds in Edmonton, scientists working at the University of Alberta found that even in places where there was suitable habitat—they examined more than 110 sites throughout the city, and seven common songbird species—“species richness and abundance of three of the seven species were reduced” in places where there was too much noise.
Report co-author Dr. Darren Proppe told BBC News, “This potential could be down to the fact that those lower frequencies [in their songs] could be overlapped by the dominant frequencies of road noise, which also tend to be fairly low, resulting in a masking of communication between birds.” It's possible, Proppe added, that songs used in selecting mates are becoming obscured or altered by the human noise and birds aren't coming together like they would otherwise.
“Mitigation of noise may enhance habitat suitability for many species,” the report concludes, rather dryly, “especially for species with songs that include low-frequency elements.”
In other words, in one way or another, to help birds we humans need to STFU.
Apart from the effect on birds, this research has got me thinking about the impact of human noise more broadly. The work of Bernie Krause is particularly interesting. For the past four decades Krause has been recording the sounds of the natural world. By natural here, I'm talking about the world apart from the human world. (A misguided philosophical notion, perhaps, but useful here for the sake of appreciating Krause's work.)
Talking with The Guardian last summer, Krause explained, “Things are beginning to quiet down in the pristine habitats. The combination of shrinking habitat and increasing human pandemonium have produced conditions under which the channels necessary for creature survival are being completed overloaded. The fragile weave of natural sound is being torn apart by our seemingly boundless need to conquer the environment rather than to find a way to abide in consonance with it.”
Abiding in consonance is great turn of phrase unto itself. But it also really gets at the heart of the matter. Nature and humanity aren't separated into something "pristine," as Krause calls nature, and its opposite—something tainted, somehow. The problem is that humanity—one part of the whole—has grown out of consonance with the rest. Our notes are not sounding in a pleasing, harmonic, stable relationship with all the others that are made, and needed.
Now dissonant music has its place. I happen to often like it, personally. But too much dissonance and a composition can quickly fall apart.
Which perhaps makes a big leap from a study about low frequency road noise and bird diversity in urban areas. But I think it's solid ground to be jumping to.
And if you haven't clicked on that link to Bernie Krause's work above, check out Wild Sanctuary. There's some great sound going on there.