Not just winter.

Oaks produce huge numbers of acorns about one season every 7 years. My yard had thousands and thousands a few years ago, for example, but very few since. Oaks seem to do this to overwhelm squirrels and ensure that a few acorns manage to germinate. Squirrels that can save acorns for years will do much better than squirrels that can only save enough for each winter.

Lots of tree species do this. They sync up and every few years overwhelm whatever eats their seeds.

Phenological event known as "masting": https://en.m.wikipedia.org/wiki/Mast_(botany)

So the same prey saturation strategy as cicadas? I wonder if that also produces a prime-number cycle preference

Similarly, periodical cicadas synchronously emerge in great numbers (more 370 per square meter) every 13th or 17th year.[1] This overwhelms predators and it's thought that the prime-numbered intervals prevent predators from synchronizing their reproductive cycles with that of the cicadas.

[1] https://en.wikipedia.org/wiki/Periodical_cicadas

Sort of hilariously overkill. Was the little guy really gonna chow down on thousands of nuts each of which is probably a days meal for him?

We have humans that save billions of US dollars, so this overkill behavior is not exclusive to squirrels.

No because humans can spend that money on things. Squirrels can't eat more than they can eat.

Nobody saw the new ice age coming. Nobody except Matthew, the red squirrel...

All the lady squirrels gonna be coming over to his crib for Squirrelflix + walnuts.

Maybe they got a family to feed

Just trying to imagine the angry spousal argument over the nuts in squirrel

Probably saving for retirement.