There's a principle in physics called the observer effect that states the observer cannot help but affect the outcome of the experiment.
I think this applies to mice.
After your advice last week I put a peanut-butter-laden snap trap inside the ductwork at the only spot that's flat. Though it was rather far from the mouse's last known location, he should have smelled it. It was upwind. Two days passed. No mouse.
Saturday morning I was contemplating a change to my bait strategy when Emmalina took a deep interest in the kitchen heat vent again. I lifted the vent cover and the unseen mouse immediately scrabbled deeper into the ductwork. Aha! He was near the top.
I wanted to use a snap trap but there's no way to keep a healthy cat out of the kitchen. The entry has no door to close and there's a window pass-through to the dining room.
So I erected an elaborate contraption which wouldn't have been necessary if I didn't have a cat. I took off the vent cover, put a snap trap near the opening and covered all of it with a cardboard box. I taped the box to the floor, not because I feared the mouse would escape, but because I knew Emmalina would overturn the box if I didn't nail it down.
Sunday morning Emmalina was sleeping on my lap when we heard the mouse climbing up the vent. I froze to wait. She jumped into action.
The mouse kept making noise until Emmy danced on top of the box and tried to dig everything away from the wall. He scrabbled back into the vent and now, 24 hours later, we have not heard him since.
This morning I again peeled the blue painter's tape from the box seam and checked inside. Nothing.
Am I too impatient or is it time for a new strategy that's less prone to error?
I don't know how to compensate for the observer effect.
(photos by Kate St. John)