I noticed this directly a few weeks ago. I was camping with a friend pretty deep in the woods, but at a campground. About a half a mile away there was an RV running a generator, which was annoying as hell, but not the end of the world. Then in the middle of the night, while we were stargazing the generator turned off, and we could noticeably hear the wildlife adapt to the change. Some got quieter, but mostly it was wildlife returning to the area. As if the sound from the generator was a forcefield keeping everything away, or at least hidden.

That last part is what really opened my eyes about the noise polution from datacenters