For the bird dropping etching,
What did the bird eat?
That is, what's in the bird dropping that makes it so corrosive. Your car's urethane clearcoat is pretty stout stuff to start with, if the acids in a bird dropping and even the corrosive elements in water are strong enough to etch urethane, there's no easy fix..
Here's the deal, anytime you have any kind of sub-surface defect, the ONLY way to remove it is to abrade the paint, (compound, polish or cleaner/wax), and level the surface with the lowest depths of the defects you're' trying to remove.
You really need an orbital polisher to do any kind of abrading work to modern clearcoats. I used to teach "hand polishing" when I was at Meguiar's teaching their classes and from my experience, 99.9% of the human population do not possess the skills or muscle to rub out a basecoat/clearcoat paint system without marring the paint at the same time.
I type this all the time,
It requires more skill to polish paint by hand than it does to work by machine -Mike Phillips
Without a garage or carport, or machine, you're in a touch situation.
Here's something else I wrote in the thread I linked to above, it's in post #4
If this car is a daily driver, not a garage queen, take it out only on Sundays to car shows and park on the grass for others to admire, then I would probably learn to live with them and just do what you're doing, wash and keep the car clean and then move on in life.
Probably not the answer you want to hear but any other remedy is going to be time consuming with some form of investment. Count the costs and again, is this a daily driver. Don't go crazy over the small stuff. And especially if you don't have garage to store this car in anytime it's not in use.
I have a small paint defect in the hood of my Lexus, the ONLY way to fix it proper would be to repaint the entire hood. Not going to do it. It's a daily driver that's parked outside 24x7 and it doesn't bother me enough to throw $1000.00 at it. Instead, I wash it, keep it clean and drive it.
:dunno: