Thanks all, for so much helpful input. After a night of looking at most of what's been suggested, I went out to look for the Puma, trying to re-create my path in the area I last remembered using it. Took my bow and a judo, thinking it would help seeing the same targets ( and I could get a few shots in ). Went in a circle or two that I best recalled, and sure enough the knife was where I had set it down after loosening a judo from a stump. Never put it back in it's sheath. Duh.
Feel a whole lot better getting that one back, it's a great knife for me. Pretty lucky.