I do have owls, I hear them sometimes, but squirrels are not active in the night time when they are. So unless they raid the nests, I think the culprit is something else. I have heard there has been a pine marten sighting around here, but most of the trees are not pines idk if that matters.
Chipmunks are as prolific as ever, dozens, so whatever it is is not grabbing them.



Potatoes are also one of the few foods you can live almost entirely on. If you eat the skin. They have about everything you need, unlike all other staple foods. The problem is you need a lot of them, and they get weird if they freeze. But you could dry them.
Peruvians used to smash them on the rocks and freeze dry them in the cold Andean air to preserve them for the winters up there above 10k feet.