Schrödinger's Mouse

Herby has been caught. After Vanessa went out to buy a more traditional mouse trap, he ultimately chose the original box trap. Once a mouse enters, the door to the trap seals itself once and a little red flag rises like the American post boxes do when there are letters waiting inside.

We were sat in the garden taking advantage of the rare appearance of sunny weather, eating an ice cream (Vanessa edit: White chocolate ice cream!) when it happened. I heard a noise from back in the house and found the trap activated when I went back inside.
We had two box traps set up, one filled with nutella and the other with green tea cake that Herby had shown a fondness for. The question that remains is which one proved to be the best lure?