Yeah, squirrels, too.
Either critter will probably get sick / die from indicidental insulation (fiberglass? asbestos?) ingestion.
Had something that seemed heavier than a squirrel running around in the attic (I'm on the second floor) a couple of years ago, but that stopped. Don't know what (if anything) the MGMNT did, but haven't heard it for a while. I was also concerned about vulnerability of my place due to a hatch going to the attic, but that paranoia evaporated.
There are many places where tree branches are close enough to the building to allow critters to get to it.
Terry, 230RN