Marten trapping isn’t complicated but tuning up boxes, trap placement and color each factor in to improved catch ratios which equals more fur in your fur shed and more money in your pocket.
Any endeavor worth doing produces greater reward with increased effort and all it takes is paying attention to the details then getting to work.
The design I now use is the culmination of my own experiences and talking with other good marten trappers. I use ½” plywood and build the boxes with an inside opening of 6” x 6” at 12” long. The notches are 1 inch at the edge of the box and tapered to about 1/8” at the 3 inch mark.
I add a bait holder using a 6” x 6” piece vinyl coated hardware cloth and fasten it with poultry staples. The bait holder is covered with a hinged piece of plywood and held closed with a home-made hasp but a store bought piece could easily be used.
The whole box is spray painted with alternating white and brown stripes. Two 2” mending braces are used to create a make-shift bracket to provide a quick way to fasten it to a tree vertically.
You may develop your own ideas about how to improve your marten boxes and that is great. Try a few ideas and compare the results this season.
The main thing is to use what you observe while trapping to continuously improve the way you trap. Your catches will increase as your understanding and enjoyment of wildlife continues to expand.