Two-stage triggers for increased sensitivity

I have several inexpensive, Made-in-China live-traps. While they are economical to purchase their triggers leave much to be desired when attempting to trap squirrels.

The typical trigger is a tread-plate that is positioned 45 degrees from horizontal and it assumes the target animal will step on it or crawl over it which will move the trip-rod and release the door.

Some of the traps have very poor execution and the opening in the side of the trap for the trip-rod is too small to allow sufficient travel to release the door. Another weakness is that some animals, tree squirrels for instance, happily hop over the tread-plate and never touch it. Other targets are so light-weight, like chipmunks, that they cannot depress the tread-plate.

If you pursue making the trigger more sensitive, you run into the issue of making it too sensitive. It will trip when you carry it. It will spontaneously trip in the breeze or when the latch feature on the door creeps.

The "engineering" solution is to implement a two-stage trigger.

I chose to use a common rat trap. It has plenty of sensitivity to be tripped by chipmunks and red squirrels but it does not have sufficient muscle to kill them.

I cut one wire to make the hole the string went through taller. Then I have a 2-by-4 with two thread-spools on deck-screw "axles".

This shows both spools.

I bent a wire to make the dog. I used a piece that I had cut from a feed-lot panel that I had fabricated into a planting-tray.

I originally used a taut-line hitch to hold the dog but the first time I tested it, it launched the dog fifteen feet. Subsequent runs were made by making multiple wraps with the baling twine and a square-knot. I retained the taut-line hitch to put tension in the line so it stayed on the spools.

But does it work?

When you walk up on the trap from this direction, you cannot see what you caught or if it was a spontaneous "trip".

My first catch was a mouse. That told me two things. One was that the set-up was significantly more sensitive than it was before. The second thing I learned is that my red squirrels are spoiled rotten and turned up their noses at peanuts.

I cracked a black walnut and rebaited with a quarter-walnut. Three hours later....

Why trap squirrels?

I figure a single squirrel can harvest at least fifty pounds of nuts. One red squirrel can easily harvest all of the hazelnuts from 10, mature hazelnut bushes.

Controlling red squirrels is not about harvesting the 4 ounces of meat. It is about protecting the nut-crop.