PSU Deer Study

After watching Mousetrap Monday videos for a week or so, I finally settled on the second tool I was going to use to reduce the rat population – a rat trap that could repeatedly capture multiple rats per night.

This was an escalation in warfare. I spent $45 on rat poison and was now investing $300 in a rat trap.

Duane on porch with Uhlik Repeater trap

The trap is an ingenious design whereby there is a hopper for bait (sunflower seeds) that sits above a trap door that empties into a cage. When rats climb up on the trap to access the bait, they trip a lever that allows the trap door to open and down slides the rat(s)! Like a rat amusement park except I’m the one having fun.

Check it out.

My very own Diefenbach House of Fun…or Horror? Either way it’s very satisfying. 

This is why I could not assess the effect of the poison completely. Remember that I mentioned rats are neophobic? I introduced the trap on May 28 – the day it arrived on my doorstep. For it to work, the rats needed to be comfortable with their new park ride by climbing on and feeding from the trap. This took a few days and I was excited to open the door for business. Also, after a rat takes a one way slide, you must transfer them from the trap before you humanely euthanize them. Otherwise, your little rat amusement park will be abandoned forever!

I set the trap on May 31. Check out what happens to rat sightings the first night I catch a rat. They drop dramatically. Are all the rats gone? We all know the answer to that question. Unfortunately, I was not consistent in my camera deployment (this is a fun summer project – I’m using science but I’m not being graded), but you can see it takes a few days before rats return to the trap. I quickly learned to open the trap for a few days. Then lock it down. Then reopen.

After a month and spending $45 on poison (no idea number killed) and $300 on a trap, I appeared to be making progress on my campaign against the rat population – at least my crude index to rat abundance seemed to at least have a downward trend (see graph below).

And by the 24th of June, my per capita trap expense had declined to $12/rat.

Looking at the blue line, rat mortalities appeared to be plateauing. With the population declining, my effort needed to increase. This is expected given what we know about the effort/efficiency curve. What wasn’t expected was the revelation of my rat nemesis, One-eyed Jack. 

Time to implement Phase III.

-Duane Diefenbach

Posts in this series:
Diminishing Returns
A man, A plan, A rat
Phase III: What every story needs

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