Nature & Outdoors
Blue Ridge Explorers: Where the Wild Things Are This Winter
By Tamara S. Randolph
When the days get shorter and the temperatures drop, we humans have to adapt. Some locals travel to warmer places to escape the cold weather. Others stay put and spend time “nesting” indoors, while the hardiest of us thrive by staying active outdoors, often in the snow. Wherever the typical winter day finds each of us, we all need to make adjustments to stay safe and comfortable.
Animals must also make lifestyle and physiological changes to acclimate to winter temperatures and snowy conditions. While we occasionally encounter wild animals who are visibly or audibly active during the harsh High Country winter, many seem to vanish.
Where are they? Let’s investigate…
Birds
A variety of animals head to warmer climes as the mercury drops in the High Country, including many species of birds who reside here during the warmer months. While some fly great distances, others simply relocate to lower elevations. Most of the birds who leave town do so gradually, without much fanfare. Ruby-throated Hummingbirds slowly disappear from our nectar feeders and fading flower gardens—most have left by mid-September. A variety of warbler species, which we hear but rarely see, stealthily flock to wintering grounds in Central and South America beginning in August.
Other migrations are very observable, and a sight to behold. During the month of September, the Grandfather Mountain Stewardship Foundation hosts a vast citizen-science project to count and identify the numerous species of raptors (hawks, eagles, falcons, and other birds of prey) as they make their annual journey to warmer climates. Every year, the public is invited to join the mountain’s naturalists as they tally the number of migrating passersby. During the 2022 migration, a total of 3,064 migrating raptors were recorded, with broad-winged hawks being the most-counted species.
Fortunately for High Country bird lovers, we have an assortment of permanent residents who stay put all winter, including the Carolina Chickadee, Dark–eyed Junco, Red-breasted Nuthatch, Tufted Titmouse, Northern Cardinal, and certain species of Woodpeckers, birds of prey, and waterfowl. These birds are able to find adequate supplies of food in the mountains year-round, but will eat extra in late summer and early fall to build up body fat. In addition, they adapt by shivering, and by trapping pockets of air around their bodies under their feathers, which they also use for waterproofing. Many birds will crowd together in shrubs, vines, evergreen trees, tree cavities and nest boxes to share body heat and stay warm. Adding safe habitat and a bird feeding station to your yard during the winter provides protection and nourishment to our hardy feathered friends and hours of enjoyment to us humans.
Mammals
Some of our common native mammals stay as active in the winter as in the summer. In or near forested areas, you’re likely to spot the following fur-covered wildlife (or their tracks in the snow): white-tailed deer, cottontail rabbits, coyotes, bobcats, and foxes. Many other mammals are all about saving energy, so they slow down while food resources are scarce.
There are several states of “slowing down,” from persistent napping to deep hibernation. Our common raccoons, Virginia opossums, and striped skunks seek shelter in the form of tree cavities, ground burrows, rock crevices, or abandoned structures. Raccoons and opossums nap alone, or with their young, while skunks may den in groups of a dozen or more. All three species enter a state of rest, or torpor, in which they lower their body temperatures (adaptive hypothermia) and metabolism, and slow their breathing. However, all must wake up regularly and forage for food to stay alive.
The American black bear takes napping to the next level. Prior to winter, black bears make their dens in rock caves, burrows, tree holes or other sheltered spots. Once the cold weather sets in and a bear settles into a den, its heart rate, breathing rate and metabolic rate slow down significantly. However, some scientists say that our black bears don’t quite qualify as “true hibernators” because their body temperature is reduced by only 10 to 15 degrees. Plus, they can wake up rather quickly from a winter nap. Although bears may not be the deepest of sleepers, their bodies still “shut down” to save energy. Amazingly, while denning, bears can go for more than 100 days without eating, drinking, urinating or defecating. According to NC Wildlife Resource Commission biologists, whether or not you consider bears true hibernators, “Bears do enter a long period of physical inactivity and exhibit some amazing physiological responses to low food availability and temperatures.”
Which brings us to “true hibernators.” Hibernation is defined as “a specialized reduction in metabolism brought about by low food availability and/or low temperatures.” Like the other mammals above, a true hibernator slows its heart rate, breathing rate and metabolic rate, and its body temperature is lowered. But these changes tend to be more extreme in true hibernators, who are also the deepest sleepers.
Eastern chipmunks, like other ground squirrels in our area, are considered true hibernators. When they enter a deep sleep, their heart rate is reduced to a mere four beats per minute, while their body temperature is lowered from around 98 degrees F to that of their burrow. During hibernation, chipmunks wake up every several days, raise their body temps to normal and feed on food they have stored in their burrows. Once they feed and pass waste, they go back into a serious slumber. Their cousin, the groundhog, shares a similar deep sleep and denning experience.
Some of our resident bat species, such as the long-eared bat and the Virginia big-eared bat, are also true hibernators. When bats hibernate, they must find a place that stays above freezing so they generally gather in caves or mines for their hibernacula, or sleep shelter, and snooze hard through the winter. When possible, bats choose to return to the same site every year.
Reptiles, Amphibians, and Fish
Reptiles and amphibians (collectively known as herpetofauna, or “herps”) experience similar physiological processes as other animals come winter, but scientists use the term brumation rather than hibernation when referring to the herps. With brumation, the animals are not sound asleep, but in a phase of dormancy, defined as “the state of having normal physical functions suspended or slowed down for a period of time.” Most reptiles and amphibians first seek out a winter home that is protected. Many burrow underground, including certain snakes, turtles, frogs and salamanders, and some of these winter dens hold large groups.
Garter snakes, for example, spend most of the year alone; however, in winter they gather near other garters and snuggle up. This helps them prevent heat loss and maintain body temperatures that are warm enough to survive dangerous conditions. Garter snakes often seek out burrows that were once inhabited by other animals, such as chipmunks. They may also find shelter under rock piles or in decaying tree stumps. Garter snakes typically brumate between October and March, but can sometimes be spotted outside of their hibernaculum soaking up the sun.
Such is the case with our native Eastern box turtles. On warm winter days, you may see a brumating box turtle emerge from its burrow; while it might enjoy a brief burst of sunshine, the turtle may actually be out looking for another sleeping hole. Some box turtles use small mammal burrows that have been vacated, while others dig into loose dirt or forest litter, burrowing as deep as one to two feet. With reduced metabolic activity, these turtles can survive on their stored fat. By April, most box turtles are awake and on the move—slowly but surely!
Aquatic turtles, including painted turtles and snapping turtles, generally cozy up in the mud at the bottom of a pond, as do their neighboring aquatic amphibians—frogs, toads and some salamanders. Unlike brumating turtles, aquatic or semi-aquatic frogs like the pickerel frog and the American bullfrogdo not have the ability to radically slow their metabolism. They must be surrounded by oxygen-rich water and remain on the mud, or only partially buried. “Sleeping” under water means that these reptiles and amphibians must breathe oxygen through their skin instead of their lungs for most of the winter.
Aquatic salamanders are generally light sleepers, and may remain active, even under a layer of ice. Terrestrial salamanders, of which there are many species in the High Country, will seek shelter in underground burrows, or under logs and leaf litter to enter a deeper dormancy than their aquatic kin. Terrestrial frogs and toads normally hibernate on land, as well. American toadsburrow deep into the soil, safely below the frost line. Spring peepers brumate in soft mud near ponds, under logs, and in holes or loose bark in trees. Some frogs have also been known to use rodent burrows as hibernacula.
What does “winter rest” mean for fish? Most fish, including our mountain trout, enter a stage of torpor, similar to the other animals we have investigated. While in their resting state, fishes’ hearts slow down, their needs for food and oxygen decrease, and they move about very little. They can go long intervals without eating and prefer to school in deeper pools, where the warmer water has sunk beneath the colder layers above.
Insects (& Other Arthropods)
A lot of people don’t miss “bugs” in the winter. But invertebrates in the phylum Arthropoda—which includes insects, as well as non-insects such as spiders, snails, mites, centipedes, and millipedes—are quite valuable to our ecosystem and deserve a lot of respect. From pollinating our plants, to enriching our soil, to protecting our gardens from harmful or invasive pests, to feeding other important species of animals, these mighty miniatures earn their seasonal rest.
Like other animals, different species have different strategies for braving the winter. A few choose to fly away toward much warmer environments—well known migrators include monarch butterflies and green darner dragonflies. Other insect species successfully pass the winter as immature larvae or nymphs, or in cocoons and chrysalises.
Most, however, tend to go dormant, including wasps, bees, centipedes, beetles, spiders, snails and a myriad of other arthropods. This state of dormancy for bugs is known as diapause, and is defined as “the inactive state of arrested development.” Before going dormant, insects/arthropods will take shelter in a variety of micro-habitats—beneath the soil, where ground temps tend to be more stable, is the choice for many, including bumblebees, ants, some beetles, centipedes and millipedes. Others seek refuge inside dead logs and hollow trees, and under rocks.
Out of Sight, Out of Mind?
If so, it’s time to think differently about all the incredible animals who share our mountain home. The next time you awake from a cozy slumber, lace up your boots, and head out for a brisk winter hike in the woods, take a moment to marvel at the biodiversity that is under your feet and all around you. Be “wowed” by the hundreds, perhaps thousands, of wild things within earshot, even though you can’t hear or see them. They are there. And when the time comes, all creatures great and small—from the biggest bear to the tiniest spider—will rise up and welcome the warmth of spring.
Tamara S. Randolph, CML’s editor, is a N.C. Environmental Educator and certified Blue Ridge Naturalist. You can reach Tamara at [email protected].
Resources:
NC Wildlife Resources Commission
The NC Arboretum
Grandfather Mountain Stewardship Foundation
U.S. Fish and Wildlife Service
High Country Audubon
The Cornell Lab, All About Birds
MSU Extension