Bird song, rain and green (a few million shades) is what I will remember most about my last trip (besides an aching butt from cycling down a very rough path)
The birds don’t acknowledge you because you are not meant to be there. They just go about their business – picking worms, cleaning beaks, singing, once in a while checking your distance and intent - and you are expected to keep out of their way. Of course they know that you exist near by knowing fully well that you cannot fly! - and therefore cannot harm them.
Birds have a sound for every occasion (I think they have more value for simple things too). Sign of food, happiness, finding their kind, everything is marked by a song/sound. And none of its singing is ever futile. We on the other hand have wasted words and that comes to us so naturally. Saving a song only happens as a “Save As” on a computer and singing ones heart out only happens at karaoke night in the hope for perfection and not in pursuit of expression.