You are right about fishers eating small animals especially in winter. Here in PA if you open to see stomach contents, you always see squirrel & rodent hairs. Fishers are tough on squirrels in my part of state. But for bait/lure in winter it's always a good idea to use a loud lure like skunk to attract animals. As BruceT said beaver is a great bait, especially with salt added to keep it louder. The fisher do seem to run the streams here, just like you were trapping for coon

No help to Zag's question, I only use hollow log cubbies with dirt hole(s) nearby.

Agree. My favorite bait- Grey Squirrel. I also pre-bait my cubbies.
Sorry Zag for keeping this topic sided track.

The mast crop theory in my opinion has enough information backing it where it cant be ignored. In Maine that is. I cannot speak for other places but Walter Arnold even wrote about it in the 1930s and the trend has stayed constant. Every other year youll hear from people pursuing marten, fisher, and black bear mostly that they either are or aren't coming to bait. The abundance or lack of natural food being the common denominator. I don't notice much difference year to year in my numbers but I do notice a difference in locations. I've made marten and fisher catches in low mast years in less than desirable locations. Also have placed traps in locations where I made a catch before in a low mast year and never caught another one in that spot again. Those are the places where I just got lucky because the critters were traveling further for food. After you get to know your fisher or marten line a few years you'll have those tried and true locations where you get them every year regardless.