Nuthatches rarely find huge quantities of food in the wild. It’s only when they find a treasure-trove of fabulous food left by humans that their behaviour changes. Normally they just eat what they find. If there’s too much food, though, they suddenly switch to Squirrel mode and cache everything they find.
That’s what’s happened to this Nuthatch. It can’t eat everything it’s found so it’s taking it all, nut by nut, and hiding it behind bark, stuffing it into crevices and coming back for more.
How long will it remember that the food is exactly where it put it? The scientific research says they can remember it for up to 30 days. Given that I can’t remember why I went into the kitchen, that’s quite an impressive memory.