Also the difference between outdoors a generation ago and outdoors now. Depending on where you are, the decrease in birdcalls is huge, but happens so slowly that most people don't know what we're missing. That loss has been happening over longer than a generation or two.
Also, there are fewer places where you hear no car noises or planes at all.
Also, there are fewer places where you hear no car noises or planes at all.
We can do something about it, but it takes work.