I gave the mice a new sippy bottle because they were having trouble getting water out of the first one, hung it at a mouse-reachable height above the bedding, and then poked the ball to make some water drip out to give the mice a hint.
Cornflower watched this, came over, drank from the bottle, popcorned in excitement, and then her little mouse brain went "πvaluable item!! what do we do with valuable items?? WE BURY THEM!!π" and she started piling up bedding until the spout was completely covered.
