Very true story. One of my engineer hats is "noise engineer". I conduct noise studies for road projects, new shopping centers (like Walmart) etc. Very frequently, I'll find that the only noise violation from a site comes from the frogs, birds, and crickets. 55-60 decibels from these critters is pretty common. If a proposed site is near a body of water, even a small pond, the ambient noise due to wildlife will pretty much ensure that the proposed development will violate the noise ordinances, because the ordinances don't specify where the noise can come from, just that it can't exist. The worst part is the nighttime permissible noise levels are usually lower than the daytime permissible noise levels. Guess when crickets and frogs make the most noise?
Occasionally, these frogs and crickets will cost our developer clients hundreds of thousands of dollars in noise remediation costs (noise walls, noise dampening materials, etc).
I was just telling the class I was teaching yesterday about this interesting little tidbit of noise knowledge. Funny this article just appeared!