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.

If you're tired of getting additional information, you can just close your eyes, get some sleep. But earlids, covering of the ears, never evolved. Not once do we find it, even in the fossil records. Because while we let our eyes relax, our ears are still hearing. And that's why alarm clocks work and wake us up. We still gather information. Every animal is gathering information 24/7. So I like to think of acoustic ecologists as people who are trying to become better listeners, 24/7.

You can listen to a birdsong, and from the content of the birdsong, you will be able to determine whether or not the bird grew up in a noise-polluted environment or whether it grew up in a pristine, clean environment. Isn't that incredible?

Not only does the modern person often think that sight is more important than sound - there's no objective evidence to indicate that. Many people, even audiologists who study the science of human speech and hearing, have assumed for a long time that the human ear evolved to hear the human voice, rather than the voice changing to fit the human ear. And the human ear is actually not a perfect match if we map its sensitivity to the different frequencies in the human range of hearing; it's an unequal curve, it's kind of a wavy line.

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

Most people think visual information is more important than aural information - like, what's this big deal about sound? And why should I bother to listen, rather than look? And here are the facts: there are blind species, in the backs of the caves, the bottoms of the oceans. It's not essential on planet Earth to be able to see, to be a species. But there are no deaf animal species. You have to be able to hear, or you won't get the information you need in order to survive.

Quiet is the element of discerning what is essential.