As the days grow shorter and the nights cooler, broadleaf trees that dominate our forests undergo spectacular changes.
Leaves transition from summer green to fantastic fall foliage, and their fruit begins to litter the forest floors. This is the first step in producing the next generation of trees.
Among the most common trees in our region are oaks. Oaks can broadly be broken up into two categories: white and red. White oaks produce acorns every year while red oaks’ acorns take two years to mature.
A single oak tree can produce thousands of acorns in a season and are a crucial component of many animals’ diets, including the familiar Eastern gray squirrel (Sciurus carolinensis).
Squirrels rely on acorns and other nuts/seeds for the majority of their diet throughout the year. When oaks first drop their acorns, squirrels investigate the acorn and decide whether to eat it immediately or store it. A lot goes into this seemingly benign behavior.
Red oak acorns contain a higher concentration of tannins, giving the fruit a bitter taste. Because of this, gray squirrels eat roughly 40% of the red oak acorns immediately and store the other 60%.
By contrast, about 85% of the white oak acorns are consumed immediately, and the rest are stored. Squirrels store acorns to sustain themselves throughout winter when food is harder to come by.
It is estimated that gray squirrels fail to recover over 70% of the acorns they bury, effectively planting oaks and propagating new trees. Many of the “planted” acorns will get eaten by other animals, but some survive.
So, the next time you see a squirrel collecting acorns, know that they are not simply hoarding nuts, but rather acting as stewards of the land.