We have mice in our ceiling. Please understand that I am not bragging. Fluorescent pink flying squirrels, bats or Screech Owls in the ceiling! Now that would be something to brag about.
They scurry about doing mice things. I sit beneath them and contemplate methods to eradicate them.
I have yet to find their food source. I put mouse traps in all the usual places. I have been catching onesie-twosie but nothing like I would catch if I had found their mess hall.
Our ceiling is of unusual construction. We have the usual trusses and rolled, fiberglass insulation. Above that we have blown in cellulose insulation.
Beneath the trusses, the builders ran one-bys and then stapled acoustical planks made from pressed paper fiber. The mice run, or shimmy in the 3/4" space between the one-bys. Maybe that is why they are so noisy, it has to be a tight fit for height.
In a way, I admire the mice. They are survivors. If push-came-to-shove, I hope I could do as well.