While we were hiking and backpacking, I kept hearing this noise in the trees and bushes which sounded like insects feasting on the trees to me. I finally had to track it down and it was only a bunch of cicadas. The cicadas at home are MUCH louder, so it surprised me. But I was relieved to find out that the trees were not being eaten up, but rather it was just the noise of cicadas rubbing their wings together.