Oak trees produce thousands of acorns every year. Somebody has worked out that an oak tree can produce ten million acorns over its lifetime. In a good year, they carpet the ground under the tree and crunch underfoot.
Acorns are an important part of the diet of many of the reserve’s inhabitants: pigeons, jays and woodpeckers, squirrels, and all kinds of mice. The deer that visit the park, roe and muntjac, will eat them as well. As the growing season closes, the acorns provide densely packaged protein and fats for creatures that need to fatten up before the hardships of winter.
Many species eat ripe acorns from the ground, where they fall, with no reproductive benefit to the tree, but some, in particular jays and squirrels, take the acorns away and cache them by burying them some distance from the parent tree. This is their food store for the winter.
Both squirrels and jays seem to be able to remember where they buried their acorns but both bury far more than they need; the RSPB has estimated that a jay can cache up to five thousand acorns in a single season. Those that are forgotten, or just remain uneaten, germinate in the following year.
For the oak tree this is an excellent seed dispersal strategy: tempting another species into cooperation with tasty, nutritious seeds, ready-packed for the larder.