The Observer Effect

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 Emmy (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 determined cat out of the kitchen.  There’s no door to close and we have 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.

We waited.

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)

18 thoughts on “The Observer Effect

  1. Your only hope is to neutralize the interference. Buy yourself a pet mouse and spend time each day introducing the cat to the new household guest. After a few months, the excitement of seeing a rodent will pass, and you will be able to catch the intruder mouse without incident from the four-pawed helper.

  2. You cannot tie up the owner of the house in another room. I think there is some kind of cat liability here. It is her house (for humans who do not have cats its a long story)!
    You have a dilemma here for sure. Homes are so much more wall less without many inside doors. Keeps our “minds” off the rain.

  3. great idea Kate!
    i do think you’ll have to lock emmalina in a room temporarily… she IS the owner as Faith has pointed out, and she will be mad at you for days afterward, but you must get the mouse!

  4. Kate, I think you should start to prepare a teeny tiny plate of turkey and the trimmings and get ready for a holiday guest! He/she just might be your Christmas mouse too.

    You get a really high mark for the box/tape contraption.

  5. Pretty ingenious idea there Kate. Unfortunately it seems Emmalina insists on being a confounding variable.

    Kathy, your comment reminded me of the year we caught a mouse in a trap in the room off our living room on Christmas Eve. That prompted me to remark to my mom “I thought not a creature was stirring, not even a mouse”.

    Also, I like Steve-o’s idea 🙂

  6. Smart mouse indeed! I have one also. It’s been invading my foodless kitchen cabinet over the last few weeks and leaving poop presents! Tried the peanut butter trick to no avail with three traps in various places. Friday night as I slept on the couch I heard the little bugger. Climbing into the dog’s food dish, helping himself to a midnight feast. Maybe they are not hungry? Could it be eating cat food?? Mine tried for a second course at 6am Saturday morning, but the dog had cleaned out the bowl. HA!!

  7. We’ve had a mouse in our house for about a month, and our cat Katie can’t catch it (even though she is superb at catching mice outside), because the mouse scurries under things (e.g., the refrigerator) Katie can’t access. We bought a trap (one that won’t kill the mouse) and baited it with peanut butter, but with no luck. We finally realized better bait would be Katie’s wet cat food, which despite our best efforts (putting it away ASAP after Katie ate) was being eaten by the mouse. We caught the mice with cat food bait within an hour of resetting the trap! We moved the mouse several miles away and released it in a field.

    By the way, it was a house mouse, not a white-footed mouse or deer mouse (the latter two native to PA and occasional previous pests in our house).


  8. Rosie!!!!! I LOVE your comment!!!! I can’t tell you how many times I have enjoyed that with my grandkids over the years. Kate, if you do not know…..It is almost as bad as “If You Give a Moose a Muffin.”

    I do believe, as someone said some postings back, this just might be the most remembered blog of all!

  9. Thanks Kathy! I enjoyed that book with my daughter many moons ago. Maybe Kate should give it a cookie! She would have quite an adventure afterwards.

  10. Well, OK–it’s December now. Have you caught your mouse? Had one in my bedroom last night causing much fun and enjoyment for my 2 cats who tried their dardendest to catch the little varmint but to no avail have no idea where it is now. Soo, have one catch and release trap under my bed and one in hallway hidden well so we’ll see how long it takes to catch this one. Since it’s holidays have too much “stuff” hanging around which makes it easier for Mr./Ms. Mouse but harder for me and cats to catch it.

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