Pay the kid next door to get out there with a bucket of warm soapy water.
A bucket of warm water. Now the bird poop isn't frozen, and you can clean it off before it refreezes.
Repeated application of a warm water soaked cloth. Will take multiple applications.
A sponge with a scrubby side on it and a vinegar. (vinegar can't freeze)
hammer and chisel unless labor is not your major concern. Then hot water, soap and a rag.
Wand type car washes.
Warm water and a cloth.
Leave it or pour warm water on it,
I always recommend licking it off!!! Poopers!
Vim and vigor