Ever find yourself in a place where there is so much noise you can’t hear yourself think? Or tried to have a conversation at a rock concert? If you’re like me, you run out gasping for quiet. Turns out birds are just like us.
All that chirping may sound like just noise to us, but for birds, every chirp means something important. There are special songs used for finding that perfect mate. Other songs serve as a warning system to alert the flock of danger in the area. Like us, birds are very sociable, they travel in flocks. Therefore, where there is a large flock, there is a large amount of chattering. Scientists have now used the latest discoveries about bird communication to develop a new, non-lethal, humanitarian way to shepherd birds away from high use areas, such as runways, golf courses, wind and solar farms, and agricultural fields, among others.
Traditionally airports have been built away from populated areas, usually in places that were previously migratory stomping grounds for birds. Since birds repeat their migration patterns, the fact that an airport has been built in their former rest stop does not alter their plans. This has resulted in a significant number of collisions between birds and airplanes. In fact, according to the Bird Strike Committee, around $1 billion in damage is caused to civilian and military aircrafts each year. The Committee’s data indicates that since 1988, approximately 250 annual human deaths result from these collisions, plus countless numbers of bird deaths.
To date, the most common methods for reducing bird population in high-traffic and high-use areas are poison, nets or guns, none of which are humane. Thanks to the innovative work of two professors at the College of William & Mary— Mark Hinders, Professor of Applied Science and John Swaddle, Professor of Biology, a high-tech ‘scarecrow’ has been developed that takes advantage of the unique need that fowl have to communicate with one another.
The Sonic Net consists of directional speakers that emit a “pink noise” that annoys the birds and interferes with their ability to communicate. Pink noise, unlike white noise, whose auditory frequencies are flat, has high energy frequencies that operate at both ends of the sound spectrum, resulting in a noise that is unbearable. For the bird, it is like being next to the stage at a rock concert. Experimenting in an active bird area near a major airport in Virginia, Dr. Hinders and his team set up a network of speakers that emitted uninterrupted pink noise for four weeks. A corresponding area served as a control group. Where there was no pink noise, the bird population remained unchanged. But in the areas where speakers were blasting out pink noise at levels of over 80 decibels, the bird population diminished by 82%. At 65-80 decibels, the population fell by 65%. And, the birds never adjusted to the noise, meaning that Sonic Net areas became a permanent danger zone for them due to their inability to communicate important information.
Sonic Net—the acoustic scarecrow—is very good news for humans and fowl alike.