For Montclair Local

November has arrived. Montclair’s human residents have spent the past few weeks transitioning to their cold-weather wardrobes; T-shirts and shorts have been put away, sweaters and sweatshirts dug out of the bottoms of draws. The heat has come on, and those with more foresight than me have had their boilers serviced. 

Our fall transitions are fairly simple. But what steps do our resident wildlife take to prepare for the arriving cold? While some wildlife (think monarch butterflies) join the most fortunate Montclair humans in fleeing south, most prepare to hunker down in place like the rest of us.

Their strategies vary widely, but for most fall is an especially busy time of preparation for the challenges of the coming months.

For many mammals, fall is marked by binge-eating to fatten up for winter. A thick layer of fat provides a calorie reserve for the winter and insulation for months of living in unheated shelters. Vegetable gardeners may noticed that groundhogs were even more rapacious than usual through September and into October, but by November local groundhogs — one of our few true hibernators — are already slumbering away in their burrows, where they will remain asleep until love calls sometime in February.

Squirrels and chipmunks combine their fat-building fall feeding frenzy with accelerated hoarding to tide them through the food-scarce winter and spring. The fall acorn crop is perfectly timed for their needs, but 2021 does not appear to be a “mast year” locally, meaning that the acorn crop will be far less than in superabundant 2019. This could mean a second hard winter for these animals and smaller populations in 2022.

Although squirrels and chipmunks are both hoarders, their strategies are very different. Chipmunks will spend the winter ensconced in their extensive burrows, with one of their underground chambers serving as a pantry provisioned with the nuts and seeds they’ve been stuffing into their cheeks since spring. 

Unlike groundhogs, chipmunks will not go into full hibernation but into a state of dormancy; their metabolism slows down, and they sleep most of the time but wake up occasionally for a snack. Squirrels, on the other hand, remain active over the winter. When it comes to fall hoarding, they observe that fundamental advice of financial counselors: diversify! 

In the squirrel’s case diversification is less a matter of holdings than of location. Squirrels practice “scatter hoarding,” burying nuts and acorns shallowly in different locations to dig up and eat over the winter. As an added precaution to throw off potential burglars, squirrels will often pretend to bury an acorn in one place while actually hiding it in another. 

Squirrels have trouble keeping track of all their scattered hoards; they will fail to recover an estimated 15% of what they bury, making the squirrel an important agent of reforestation.

Some mammals also change their housing arrangements as fall progresses. Squirrels move from their summer leaf nests suspended high up in trees to more sheltered tree cavities; they are not above moving into even more sheltered attics if the opportunity presents itself. 

Skunks will often move into abandoned groundhog burrows, where they go dormant over the winter after sealing the entrance with leaves. In an arrangement unthinkable for the anti-social chipmunk, both squirrels and skunks will sometimes take in roommates for the winter, cohabitation providing warmth.

Of course, mammals are not the only wildlife to become especially active in fall in preparation for winter. Anyone who closely observes fall-blooming native plants, such as goldenrods and asters, will notice that they are alive with a rich variety of bees and other pollinators ranging from the conspicuous and easily identifiable bumblebee to bees so tiny as to be almost invisible. The bumblebees active late in the fall are mated queens, who gorge on pollen in preparation for hibernation in shallow winter burrows protected by a layer of leaves until they emerge early in the spring to go about building next year’s colonies. 

While by now the monarch butterfly has made its way to Mexico, its copycat, the viceroy, doesn’t join it in the long migration. Instead, it stays here in caterpillar form, rolling itself up in a cozy leaf of its host plant, the willow, to pass the winter. 

Other common and charismatic butterflies, such as the tiger swallowtail and black swallowtail, go into chrysalis form in the fall, attaching themselves to tree bark, plant stems or dry leaves, and wait to emerge as adults in the spring. Some butterflies even stick out the cold months in adult form; the comma butterfly’s yellow-brown coloring makes a perfect camouflage as it hides out in fallen leaves.

One otherwise beloved insect, the ladybug, has recently developed a bad reputation for moving en masse into attics for the winter. The culprit is not our native ladybug but its invasive Asian cousin. 

Native ladybugs are perfectly happy to overwinter in adult form outside in hollow stems, under tree bark or in leaf litter. Yet another reason to minimize fall cleanup: “Leave leaves,” and let plant stems stand. 

With the stress of preparing for upcoming holidays, the depressing shift to longer and longer nights and the semiannual challenge of remembering whether to set clocks forward or back, who needs to devote time and worry to unnecessary yard work? 

Think of the dry stems as aesthetically pleasing winter interest and the fallen leaves as free natural fertilizer and mulch. At the same time, you are providing essential winter habitat for pollinators and other beneficial insects.


In “What’s in Your Backyard,” Sanford Sorkin and David Wasmuth alternate writing about the birds and beasts you may see around your house. Wasmuth is a local environmentalist and amateur naturalist. He is a Rutgers Environmental Steward and the founder of the Montclair Backyard Habitat Project. Seen a bird or animal you want to know more about? Write to us at