Squirrels, Chipmunks, And All Those ACORNS

by Marjorie Rachlin

“Be prepared, winter is coming.” Squirrels and chipmunks have gotten the message. All over Forest Hills you can see them moving into winter quarters and filling up the pantries. This fall’s bumper crop of acorns is good news – a handy supplement to our bird feeders. (More on all those acorns, below.)

For squirrels, the ideal winter apartment is a deep hole in a big tree. If they don’t have a hole, they will stay in summer nests, those big bunches of leaves and twigs we see in the tops of trees. They are called “dreys” in the scientific literature.

Squirrels don’t hibernate, so we will be seeing them all winter, but they need to fatten up now. Often a grey squirrel will sit on my lawn chair turning an acorn round and round, gnawing, until the shell is off. Then he or she chows down.

After that it’s back to collecting. If you watch, you will see that squirrels investigate several acorns before putting a “keeper” in their cheek pouches. They reject an acorn that has a hole or has been eaten inside by insects. They are also fussy about acorns that have sprouted – they bite off the sprout so it will not grow anymore if they keep it.

Then they cache the nuts, usually by burying them in the lawn or the flower beds a few inches deep. This is their winter store. How do they find them again? Some experts say they have a great spatial memory and use landmarks; others disagree. All say that the squirrel has a good sense of smell, which helps it find its cache. As we know from experience, they miss a lot – thus helping to replant the forest.

We have a lot of squirrels in Forest Hills, but it’s a wonder we don’t have more. In an area like Forest Hills, rich in oaks and nut trees, the female usually has two litters a year, one in February/March and another in June/July. That’s the explanation for all that chasing around in January and May – the males are competing, although they do not actually fight.

There are 2 to 6 babies in each litter and they stay in the nest with their mother for ten weeks. After that they leave and are on their own, although several squirrels may den together in the winter.

Squirrels take advantage of our bird feeders and most eat well all winter. They can be a nuisance, but on the other hand, their antics and play are a joy to watch.

Chipmunks: The long sleep

Chipmunks, on the other hand, are going to spend the winter underground, coming out occasionally if the weather is warm. A chipmunk has a burrow of 12 to 30 feet in a maze of branching tunnels. When it gets cold, the animal sleeps there for two or three weeks, then wakes up, eats a meal, goes back to sleep.

Since their supply of food has to be in easy reach, they dig several chambers in their burrows. These are filled with nuts from oak trees, walnuts, hickories and beeches. One expert says that a chipmunk may collect 1000 nuts.

Chipmunks have their own fussy take on acorns. They like to find one that has a little hole in it, indicating that a weevil laid an egg there. They can probably tell if the egg has hatched into a grub. Then they gnaw it apart and eat the grub, a good source of protein. Nuts in good shape they put in their cheek pouches and take them underground.

Balance of Nature

A Forest Hills resident tells me that she has two red-shouldered hawks that sit on her porch railing, watching all the squirrel and chipmunk activity. Occasionally one of them swoops down and catches a meal. Predators like hawks and raccoons help keep the population down, and many also die from disease or food scarcity.

Why so many acorns?

Remember last spring when we were sweeping pollen off our porches and dusting off our cars? That was oak pollen, from those two-inch yellowy tassels hanging from the trees. Wind blows the pollen around, and some of it lands on the female flowers of the oak, which is little inconspicuous flower on the twigs.

Last spring had just the right combination of temperatures and wind pollination for our white oaks, the ones whose leaves have rounded lobes. This happens every 3 or 4 years, according to the books. A grown white oak can produce 10,000 acorns, and they have had a good year. Our black/red oaks, on the other hand, are bare. They bloom at a slightly different time – maybe next year, they will produce.

This accounts for the bombardment that Forest Hills residents got in October. Now there are white oak acorns everywhere on our lawns and gardens. White oak acorns sprout immediately, but luckily a lot of the tiny oaks die an early death.