The Mice are Scared!
I ventured up to the third floor today and noticed a great reduction in the quantity of mouse poop around the center of the floor near the traps. The traps haven't caught anything in a while. The mice must have been scared off! They must have heard about the mummified remains of their great ancester that I found. Maybe it was the sight of the mummified head mounted on a toothpick and posted near the entrance to their nest as a warning!