By the way, it is bats. The critter guys came and indeed we have a colony nesting under a loose shingle in the back of the house. To further protect their brood they have gnawed a hole in the wall which is why we can hear the scuttling and tweeting so clearly inside.
Bats are protected so their nests cannot be cleared out (interpret that as you may.) They will remain safe and sound until mid-August when all kinds of nonsense will take place. We will basically hint that perhaps they have overstayed their welcome and then install a contraption to discourage their reentering their/our home.
This will take place after our return from a house in Colorado where sightings of mice, voles, bears and mountain lions are not uncommon.
Did I mention that I have a headache?
Bat images found here.