I'm thinking about putting some marten and fisher body grip boxes on the ground instead of trees, but have had problems in the past with mice chewing the marten fur. They catch just fine, but if I'm going to lose it to rodents I'd rather not get them.

It seems to me that I saw a post here that used a pole nailed to tree that would lift the animal after the catch to keep it safe; but it was using leg-holds which I can't legally use. If I remember right that one had the counterweight pole held down with a single finishing nail through the trap chain that the animal would pull off and get hoisted. Anyone have an idea how I can adapt that to a body-grip? Most of my animals never make it out of the box so I can't count on the animal triggering the hoist pole by pulling. There's probably something simple that I'm over-looking.

Seems to me the trap itself would have be the trigger to lift the trap. The trap springs could easily pull a pin that holds a big rock or tree branch up.

Yeah, I was thinking some sort of toggle that the spring would release

Some good info on marten sets in the archives wilderness forum , with some good ideas.

The body grip spring fires and thus springs the pole from it's position. Just put the line by the nail in front of the spring, then it will push the line, break the line, or push the nail off the other nail, and then the pole pivots, lifting the marten. Not a good idea to set traps for Marten on the ground. I understand this is why you want to know how to do this, but I suggest just making a traditional elevated marten set. You said it yourself.... "but if I'm going to lose it to rodents I'd rather not get them." If you don't have a perfect system to lift the marten up, you just lost a lot of money and a valuable fur animal to boot. There are pictures in the archives wilderness forum if you just have to do this. Tree nailed to another tree, pulled down by fish line, trap fires breaks line, pole goes up with Marten attached to pole. Hard part is getting the right pole and balance, a lot of time to make these. Hope this helps.

I put my traps in the trees now, or at least nearly all the time. Still occasionally get squirrel damage even at that.

It just occurred to me now that a Coni-clip might be a fool-proof method. Trap fires, releases from the clip and up it goes.