Found the mousie. (Or, possibly, a second one -- wild mice look the same to me.)

[xiphias]

Nora was sitting in on the bathmat with a rather smug expression. There was a dead, chewed mouse on the floor next to her. We praised her and flushed the thing.

The weird thing is that we figure that one of us ought to have heard her either digging the mouse corpse out of where it died, or, if it was a new mouse, heard her hunting it. So, no idea.