Whenever you're in a natural system and you're making sound, you are putting yourself at risk. As you go up the evolutionary ladder, from insects to frogs to birds and on up into mammals, the higher intelligence recognizes that when you vocalize, you put yourself at risk. So mammals generally vocalize or make noise much more rarely than, let's say, insects or frogs. And when they do, and put themselves at risk, it has to be worth the risk, and have true meaning, such as signaling during a hunting party, calling in prey, some religious or spiritual ceremony, something like that.

What visual information does is it creates priorities. You cannot know with certainty what lies behind something else. There are very few transparent materials in the natural world or the built environment. And so we deal with things superficially, and we deal with what's in front of us, not what's behind our head that we can't see, or to the left or the right. Visualists are often linear and timeline-oriented, whereas the natural condition and the natural way of problem-solving throughout evolution is to be multitasking.

The normal way of gathering information is through sound: when you hear information that you want to gather, you look in its direction, you see what it is, if you choose you can get closer, you can see it, you can touch, and then, finally, the most committed form of data gathering is to taste it and eat it. But for the urbanite, we're cut off from our primary sense, and I want to stress that - our primary sense of gathering information about the place that we're living in - and instead, we're in a war zone.

Often how you define the problem will determine whether or not you're able to find a real solution.

I used to hate the urban environment and the urban din. But I realize now that it's really not that much different than living next to a waterfall for wildlife. Most wildlife - unless they're specifically adapted - avoid being around a waterfall or whitewater streams and rivers because it jams their sense of surveillance. They are more vulnerable, and their message loses intelligibility. Now, the ouzel is able to overcome that in various ways. Back to the urban environment, we're talking and delivering messages as if we weren't next to a waterfall, and that's a problem.

An acoustic ecologist is a listener who is aware that sound is information. It's information because it's created by events, events produce sound, and that sound has all kinds of data, if you will, that conveys what event occurred, what the materials were, whether it was sudden, slow, loud, in what direction. And because it is information, we can think of it as a message. The acoustic ecologist studies information systems that are both intentional and sometimes wild.

The birds are already evolving, changing the way that they sing as a result of noise pollution. And we have yet to do that. We're still not communicating. We're not changing our words. We are not testing, not providing this new lexicon for noise-polluted areas.