“Not a creature was stirring…”
Oh, yes they were. Winter is the time for rodents to try get into our homes. Birds including pigeons also will roost within attics and can cause some real issues not to mention the noise. You might even think you have ghost, OK I’m kidding about the ghost. But noises should draw your attention to possible critters in the attic, the sooner you solve this problem the less chance of BIGGER issues. Remember parasites and other pests can create some issues bigger than what you might of had.
Rodents will burrow into and through insulation, animals/wildlife can also set up home with the walls of that attic. So keep an eye out for burrowing and rodent feces.