I understand that birds poop on cars - and that if you park under a tree, it's an open invite.
When we moved into the new house, the garage was filled with building materials, and some random junk. It's nearly cleaned out, but it's not yet in a state to be parked in. In the meantime, we're parking outside the garage - under a tree.
There is more poop on my car than I've had on any of the cars I've owned combined.
A quick sample.