I CAN'T say that I expected to be sunbathing in November, but on the second of the month I was doing just that while leaning on a big, old oak tree in a sunny glade within Slingsby Banks Wood.

The unseasonable warmth was so delicious that I closed my eyes and may even have drifted off to sleep had the parrot's squawk not kept me awake. Parrot? I have nodded off after all and am dreaming of tropical rainforests. No, there it is again – and there's the bird itself.

My lazy stillness turned out to be very fortuitous because the jay had not seen me, so this is normally very shy bird was allowing a much closer view than normal. Not only was I able to admire it's striking plumage (mainly pink with black wing-tips, a white rump, chequerboard forehead and electric blue wing patches) but also witness a fascinating bit of behaviour.

Lying on the ground beneath the oak tree were thousands of freshly dropped acorns and the jay was eating them, or at least that is what it seemed like at first. He would pop a couple into his throat pouch, hold a third in his bill and fly off, only to return a minute or so later to repeat the whole process. When this had happened for the tenth time I realised what was going on. The jay wasn't eating the acorns at all (a belly full of 30 acorns would've made him too heavy to fly anyway!) – he was snaffling them away somewhere to eat later.

This behaviour is called "caching" and can be a real lifesaver for jays in late winter and early spring when food is very hard to come by. Each individual bird buries in the woodland leaf litter an incredible 2,000 to 4,000 acorns, but not all in the same place. Working on the not-all-eggs-in-one-basket principle, jays hide each mouthful of acorns in a different location and, most amazingly of all, they remember where they all are.

Early next year, my jay will re-visit each of his November hiding places and eat every acorn, or better still, tasty oak seedling that he finds. Researchers estimate that jays find more than 80 per cent of their hidden caches which is great news for them but not bad for oak trees either. The remaining 20 per cent of acorns have been spread far and wide from the parent tree and carefully planted.

Jays are not the only animals interested in acorns – these highly nutritious food packages are also eaten by squirrels (who also hide them away in caches), mice and badgers.

Historically Ryedale's woods also supported populations of wild boar which would eat eat acorns by the ton. They have not been around for a few hundred years but their domesticated cousins have the same tastes and up until the last century pigs were routinely allowed to forage in oakwoods."Pannage", as it is known, was allowed to happen for 60 days in autumn to fatten the pigs up for the winter.

If acorns are so good why don't we eat them? Good question. The truth is that a lot of effort has to be put in to get rid of the bitter tannic acid and tough shells. We don't bother now but our ancestors certainly did and some readers may even remember hard times in the 1940s when wartime austerity meant feeding acorns to the chickens and even roasted acorn coffee substitute for breakfast.