This morning, I received a machine-translated message from an aliexpress vendor, apologising that their production had slowed due to the coronavirus pandemic, and so my geiger counter still hadn’t shipped. In a very 2020s way, that reminded me to make a blog post about a recent breakthrough in my ongoing battle against pestilence!

Most of the trapping I do is with a local volunteer group, mainly targeting larger pests than mice: possums, rats, hedgehogs. I keep a shopping bag hanging in the basement with supplies for trapping excurisions, including lure, and a couple weeks ago I was somewhat amused to discover that a mouse had itself discovered the bag. In subsequent days I grew increasingly frustrated by my failures to kill this mouse, and its increasing boldness. It could clean the lure off a snap trap without springing it, over and over again; I’d try to adjust the trap to be more sensitive but the mouse persisted. One day I made several trips in/out of the basement through the day, and actually saw the mouse three of those. That evening I sat on my workbench for a while with a cocked air rifle, and saw the mouse a fourth time. Raising the gun spooked it in to hiding before I could take aim.

Traditional snap traps rely on a bit of downward pressure on the trigger to set them off - the mouse has to push down on the trigger while it eats some lure. Setting the trap as sensitively as I could, so it was just barely possible to place the trap without setting it off, wasn’t good enough for this mouse. I realised that a simple modification though, would make the removal of the lure directly trigger the trap!

The idea is pretty simple, and I’m surely not the first person to think of it: if the locking bar 9 is bent in to a more bowed shape, then the trap won’t stay set - any attempt to set it trap will cause the trigger 11 to pivot, releasing the locking bar and then the spring “of sufficient strength to force the jaw violently against” a delicate typing finger. So, do that, but first stick a little piece of nut under the trigger so that it can’t pivot out of the locking bar’s way.

This makes the set mouse trap quite robust so it’s easy to place, and the mouse woud have to pull an Indiana-Jones-style stunt to get away with the nut. I killed 3 mice in the first 24 hours with this new arrangement.