T HE ground is covered with a white shroud and trees and shrubs are hung with icy pendants that glisten brilliantly in the sunshine. February is here; and, as winter advances, my thoughts turn to the birds and mammals still abroad in field and forest, battling chill winds, swirling snows, and freezing temperatures, and gambling their lives against a diminishing food supply.
As I observe these brave and hardy creatures I am amazed at their physical vigor. The chickadees think nothing of being out in a driving snowstorm. The kinglets feed unconcernedly, though the north wind howls and pine branches groan beneath heavy burdens. The shrews hunt even during sub-zero weather, when biting winds sting our faces and crusted snow crackles underfoot.
I am so accustomed to seeing the chickadees that I take their presence for granted. But whenever I see the kinglets, I never cease to wonder how these dainty birds, seemingly so delicate and fragile, manage to survive. Even more surprising is how the shrews get through the winter. I should expect such diminutive animals to seek refuge when the first frosts whiten the ground in the autumn and remain hidden until the rays of the spring sun begin to warm the earth. Instead they are as active as in summer, hunting at all hours and in all sorts of weather. I frequently find their elfinlike tracks in the snow, but I do not often see these mouselike animals because of their size, quick movements, and habit of working under cover. Occasionally, I do come upon one of them poking his delicate snout into a crevice in the bark of a tree trunk in search of insects, or ferreting about in the leaf mold or among decayed pieces of wood.
How these little animals hold their own against adverse climatic conditions and a host of natural enemies is beyond understanding. Yet the shrews are widely distributed and are abundant in many places. I suspect one reason for their successful fight for survival is that they seem able to adapt themselves wherever there is shelter and food, apparently as much at home in the dark, moss-carpeted spruce forests of the north as in our own deciduous woods, grassy fields, and marshes.
We often mistake shrews for mice or moles. They resemble both, but they may easily be distinguished from the mice by their pointed noses, small eyes, and finer fur, and from the moles by their smaller size and mouselike feet. Perhaps if shrews were seen more often we might recognize them, but one seldom gets more than a glimpse of them as they rustle among fallen leaves, or dart from one fallen log to another.
Their food consists of insects, snails, small annelids, and other food that they can capture. It doesn't seem possible they can find enough of such fare during the winter to subsist, but apparently there are sufficient dormant insects to supply their needs. Plants are eaten sparingly, but if their preferred diet is not available they can live on a plant menu for many days. Because of a very rapid rate of digestion, they require an enormous amount of food and literally eat all the time. If deprived of food for several hours, they starve to death as I discovered when I tried to keep them as pets and found that they require almost constant attendance.
Despite their small size—they measure barely four inches in length and weigh only a few grams—they are highly predatory, courageous, and pugnacious little animals and will not hesitate to attack creatures several times their own weight. Except for repellent scent glands, which do not seem too effective, they have no defense against their natural enemies. Owls, hawks, shrikes, herons, and mammals, such as foxes and weasels, prey upon them with impunity. That many shrews fall victim every winter may be seen by the large number of their bones in owl pellets alone.
Thinking of the shrews, I cannot help comparing these tiny yet hardy animals, who must hunt constantly for food, with the clumsy, lumbering porcupines, who find plenty to eat in the bark and leaves of evergreen trees and need bestir themselves so slightly for their meals. Deer, too, have food ready at hand in twigs and the foliage of evergreens, but heavy snows and drifts often make travel so difficult that many perish from exhaustion and starvation. And other animals find the season one of hardship. As the snow cover deepens and food becomes scarce or unavailable, gray squirrels make use of tunnels to hunt for buried nuts, and weasels, mink, and others, made bold by hunger, roam far and wide in search of prey.
This is one time of the year when the weasel is not likely to kill for the mere pleasure of killing. I know of no animal who has a greater lust for blood. Here, indeed, is your true predator. Bold and inquisitive, with a high degree of cunning, and utterly without fear, he is quick, sure-footed, keen of scent, and relentless in pursuit. It is probably true, as has been said, that he is the most perfectly organized machine for killing ever developed among the mammals. His teeth are designed to seize prey and his jaws are provided with powerful muscles. His ears are attuned to catch the faintest squeak of a mouse and his extraordinary wiry, lithe, and muscular body permits him to follow his prey to the deepest recesses of their retreats. Add to all this a sharp nose and a low forehead in which are set a pair of small, penetrating eyes with a cunning gleam and without the faintest suspicion of mercy, and you have an animal which might be described with one word—rapacious.
And yet, paradoxically, the weasel, of all our wild animals, is, perhaps, of the greatest value to the farmer. At times he inflicts considerable damage on poultry, but on the credit side of the ledger he is one of the most effective checks on the hordes of meadow mice and other rodents which so often destroy forage crops, orchards, vineyards, and garden produce. Providence seems to have assigned him the mission of keeping these pests under control, for whenever a weasel appears mice and other rodents rapidly diminish in number.
I do not doubt his change of coat from brown to white helps him to capture his prey, but I rather suspect his change of dress is of more value as a means of protection for, surprisingly, this fierce marauder is subject, in his turn, to the law of fang and claw and often falls victim to wolves, foxes, and birds of prey, although how such animals succeed in catching him is something of a mystery.
The mink, unlike the weasel, though a member of the same tribe, does not bother to change his coat but remains brown throughout the entire year. I have often found his tracks along a snow-covered bank and have frequently seen the animal dodging in and out of the ice-free water, or swimming beneath the surface in pursuit of prey, for the mink is an expert swimmer and is as much at home in water as on land.
At this time of the year, when still waters are frozen, the mink will haunt open rapids and warm springs in the woods. Frequently he will run beneath the ice of a closed brook, if he can find an opening in it and if the water in falling away has left a narrow strip of unfrozen turf beneath ice and snow, for it is in such places that meadow mice spend the winter, their burrows opening out from the banks in the same manner as those of muskrats. But water is not essential to his happiness, and if streams freeze he will enter the woods and hunt rabbits and such other animals that he can capture.
I wonder what would happen to preying animals, such as the weasel and mink, if the meadow mice and other rodents were suddenly to diminish in numbers; certainly they would find it difficult to exist. But the meadow mouse, for one, is a prolific breeder and one large litter follows another in rapid succession, until it seems as if the countryside would be overrun with them. But their enemies are many, and from air, land, and water a constant menace threatens, ready to snuff out their lives in a savage rush of wings, feet, or fins.
Meadow mice are active throughout the winter, scurrying about in their runways beneath the snow on trips of exploration for the blanched shoots of grasses, seeds, and hardy rootstocks. Many doorways lead to the upper air and at night the mice scamper back and forth across the snow. If we could read their tracery of footprints on the white surface, as they lead from tree to tree and to stump and rock, what tales they might tell, tales of adventure and daring. For what other reason would they leave the comparative safety of their tunnels to venture forth where danger lurks from fox and owl?
I have been curious, too, to know why the deermouse stores up vast quantities of seeds, nuts, and other edibles, and then, instead of staying home like the chipmunk, runs about when cold weather comes. Even on the most bitter nights of winter, when countless stars form a canopy over the tree tops, biting winds hiss through stiff branches, and snow is piled high over tangled brush, the deermouse is abroad, skipping along the snow from tree to tree and shrub to shrub.
Doubtless it is the call of high adventure that lures him forth. To maintain a nightly revel, however, he must draw heavily on his stored-up food supply and, as winter begins to wane, his supplies are often nearly exhausted. So, too, are the seeds and berries which remain on shrub and tree, for others besides himself have dined on them. Is it any wonder, then, that he is thin and shabby when spring comes, no longer the round-bodied, handsome creature of autumn?
Like the mammals, our wintering birds find it necessary to search assiduously for enough food to keep them alive, and for this reason they often eat berries and other fruits which they normally ignore. The scarlet pennants of the barberry, made sour presumably by a provident nature so that summer residents and fall migrants leave them untouched, now become life-saving food. And the bitter, velvety, crimson plumes of the sumac, showing like flaming torches against the sky, are eaten with avidity by such birds as the chickadees and blue jays. But even such food sometimes becomes inaccessible when winter goes on the rampage; only the crossbills seem unaffected by heavy snows, for the evergreen cones on which they feed are usually above even the deepest snow cover. Actually they don't feed on the cones but on the seeds, which they scoop out with their tongues, after prying the scales apart with their curiously crossed bills.
At this moment of writing, a brown creeper is busily exploring the trunk of a towering elm outside my window. This little feathered brownie reminds me of the nuthatch, for he has the same habit of spiraling around the trunk, though he starts at the bottom and works his way upward. He spends most of his time searching for insects, and while his may seem to us an unexciting existence, he appears to be happy and contented and will occasionally burst into a long and ecstatic song in March and April.
I think most of us are unaware of the many plants that remain green throughout the year. The snowberry, bearberry, checkerberry, partridgeberry, mountain laurel, sheep laurel, pipsissewa, and inkberry are only a few that add a touch of summer to the winter scene. There are the pines, spruces, and hemlocks, too, but somehow they escape our notice, and what a pity, for the spruces and hemlocks, their white robes glistening beneath dancing sunbeams, are never more effective than at this season. The pitch pine, too, at all times a sturdy tree, never seems so rugged as when its spreading, scraggly branches groan beneath a burden of snow.
There are many other features of the February landscape that remain unnoticed by most of us. Stroll along a snow-covered woodland path with an observing eye and you will find much to intrigue you. Note the bracket fungi, in greens and reds and browns, encircling old stumps, or stiff and white, standing out from crumbling or fallen moss-grown boles. Note the naked trees, silhouetted against the winter sky, and the grotesque shadows they cast on the whitened ground. Entirely disrobed, they reveal in complete nakedness their separate individualities. Compare the angle at which their branches grow out from the main trunk, the degree and direction at which these branches curve, the appearance of the bark, the arrangement of the buds, and you will find points of dissimilarity which will enable you to recognize them, much as you distinguish your friends by the color of their hair, the tint of their eyes, the curve of their lips, the tilt of their noses. You will find it, if I am not mistaken, a charming and fascinating study.
You will also discover, as you become acquainted with our silent companions of the woods and roadsides, that they are often disfigured by swellings on the twigs and branches or by other peculiar deformations. Sometimes these outgrowths or excrescences, which are known as galls, are not particularly noticeable, but at other times they flag attention. Irregular bud deformations of the black birch may escape the eye, but the dried remains of the flower-gall so disfigure a white ash that they are rarely passed unnoticed. Occasionally a hackberry is found with so many of the so-called "witches-brooms" that the galls might almost serve to identify the tree, and frequently an oak will be adorned with so many oak apples that it looks like a leafless apple tree with last year's fruit still hanging from the branches.
Frequently the naked twigs of many choke cherries appear from a distance to have been charred by fire, but a closer examination will reveal the branches covered with black, compact, rounded, swollen masses. These masses are caused by a plant parasite, the black knot. To some extent the presence of this parasite might be used to distinguish the choke cherry from the wild black and red cherries, for though the parasite occurs on all three, it is more abundant on the choke cherry.
On the nude branches of many trees you may find the winter retreats of various insects. The trim, leaf-wrapped cocoons of the promethea moth look very much like dead leaves and hang straight down from the branches of such trees as wild cherry and sassafras. Many years ago I found hundreds of these cocoons in a clump of sassafras. I took a number of them home and kept them outdoors in an insect cage. One day, after the warm weather had set in, the moths began to emerge and soon the cage was filled with them. I let most of them escape but kept a few for breeding. Within a day or two the females deposited whitish, brown-stained eggs on some leaves which I had provided, and after the eggs had hatched I reared the caterpillars until they spun their cocoons, thus completing the life cycle. I gave the cocoons to some young entomologists and I am glad to report they kept them safely until the following spring.
If you live in eastern New England you may find the nests of the brown-tail moth on the twigs of such trees as maple, elm, oak, apple, pear, and wild cherry. The nests are small, firm-webbed retreats of silk and leaves, and are usually placed at the ends of the twigs. Like the gypsy moth, the brown-tail came from Europe and made its first appearance near Boston, but unlike the gypsy moth its manner of arrival is unknown. The moths are white with yellowish-brown hairs at the tip of the abdomen. The caterpillars spend the winter within their nests, when a third or half grown, and when fully matured have tufts of white and brown hairs. These hairs, especially the brown ones, carry an irritating poison and if the human skin is exposed to them cause the "brown-tail rash."
Many other insects spend the winter in silken nests. One that comes to mind is the Baltimore checkerspot, a butterfly found in swamps and wet meadows during June and July. Like the tent caterpillars, the larvae have the habit of working together for the benefit of all. As soon as they hatch, they spin a silken tent for their home. They enlarge and repair it as necessary, and though they often wander from it they generally return to feed and molt. After the third molt, the caterpillars stop feeding and become more or less dormant. This fast may begin as early as the middle of August, and the caterpillars cannot be induced to eat until the return of spring. They will not even feed in the southern part of their range, where they would have plenty of time to mature as butterflies and to produce another generation of caterpillars that could pass the winter. Evidently the instinct to bridge the winter as they do has become so firmly fixed after countless generations that it cannot be changed.
Although the caterpillars feed on various members of the figwort family, they seem to prefer the turtle-head. Look for the silken tents on the withered stalks and if you fail to find them, which is not unlikely as the species is not common and very local, look, instead, for pitcher plants, which are to be found in the same sort of environment, and you will discover many other interesting insects hibernating within the leaves.
February, in many ways, is a month of contrasts. Normally a month of cold and snow, there are days when spring is in the air—days when the mercury climbs high and howling winds give way to gentle zephyrs; when a benign sun warms a frozen earth and melting snows cascade along rock-ribbed gullies; when butterflies flit about in a sunny glade. Butterflies are certainly not a part of winter; we think of them as part of the summer scene, flitting about lazily in the sunshine,
Yet I have often found mourning cloaks in February flying about in the snow-clad woods. These butterflies hibernate as adults in a convenient shelter and often emerge on mild winter days and fly about from tree to tree. They remain abroad only during the warmer parts of the day, and as the temperature begins to drop they disappear one by one, returning to their winter quarters until the sun's rays again call them forth.
So far as I know there is only a single brood of this species in the northern states. The individuals seen in February are the ones that emerged from their chrysalids in July. They are also the same ones seen in autumn flying about in the sunshine before seeking their winter quarters, where they remain, except for brief flights during the winter, until May, when they lay their eggs. Thus they live for ten months as adults, an extraordinarily long time for a butterfly.
The mourning cloaks are not the only insects to be seen at this time. On warm days gnats fly about, sometimes in small swarms and at other times by the thousands; snow flies emerge and walk over the snow; and diving beetles rise to the surface of ponds and streams. The diving beetles spend the winter on the bottoms of ponds or under banks, where they remain in a dormant or semidormant state, except when they are attracted to the surface by a rise of temperature. I always delight in watching these insects move through the water, for they swim and dive expertly. They are well adapted for an aquatic existence, having an oval body, which lessens water resistance, and long, flattened hind legs, that serve admirably as propelling organs.
Diving beetles are usually black or brownish marked with yellow. They have slender antennae in contrast to the club-shaped ones of the water-scavenger beetles with which they might be confused. Some of them are an inch and a half long while others are very minute. But big or little, and in either case quite innocent-looking, they are fierce and voracious and a terror to the other small inhabitants of pond and stream. They frequently hang head-downward from the surface of quiet waters, and if you observe them carefully you will see that just before they dive they lift their wing-covers and take in a supply of air in the space beneath them, which they use to breathe while submerged. I have frequently taken these beetles home, as they make interesting aquarium animals if well supplied with food, and, though I have kept them alive for several months, I never succeeded in keeping them as long as Harris, who kept one "three years and a half in perfect health in a glass vessel filled with water, supported by morsels of raw meat."
The appearance of the diving beetles may lead one to suspect they are the first manifestation of renewed activity in our ponds and streams. This is not so, for many animals living in our fresh waters are active throughout the winter season. I distinctly recall a February afternoon when I was poking about in a shallow but swiftly flowing brook and a two-lined salamander suddenly slithered from beneath a flat stone. Since then I have found many of these salamanders, for they are among the ever-present winter inhabitants of our swift shallows.
Nymphs of various May flies are also abundant in swift rivulets and spring-fed brooks, where they feed on the green algae, which they scrape from the rocks, or on the soft silt, which they sift and swallow. And brook leeches, often with young attached, may frequently be found clinging to the undersides of rocks. These leeches do not suck blood but feed entirely on aquatic insects. They are oval, flat, and olive green in color, with two lines of black dots near the center of the dorsal side. In the colder parts of spring-fed brooks, scuds swim jerkily about, searching for food and in turn being eaten by brook trout. These little animals—distant cousins of the shrimps, crabs, and lobsters—are the acrobats of the water world, for they can climb, jump, swim, or glide with equal ease. They are shaped like fleas, with arched backs and narrow bodies, and have appendages for climbing, swimming, and jumping. Apparently Nature was in an expansive mood when she created them.
The larva of the dobson fly, commonly known as the hellgrammite, is another active inhabitant of rapid streams. I use the word "active" advisedly, for if the water grows cold the larva will become sluggish and feed indifferently. As the temperature rises, it springs into renewed activity, probably to the dismay of other aquatic insects, since it is a fierce predator, a devouring enemy of May flies, stone flies, and caddis flies.
Averse to light, it hides by day in a hole or in a crevice beneath rocks, and is seldom seen unless a stone is suddenly pulled out. I have found it occasionally but more by accident than intent. It is a queer-looking creature and so unlike the adult fly that the two hardly seem related. But there are countless similar instances in the animal world of young being unlike their parents, so it is not altogether surprising.
Although the earthworms at this time of the year are deep in the ground, their relatives, the bristleworms, are active by the millions in ponds and streams, where they overturn the ooze of the bottoms as effectively as the earthworms overturn the topsoil of the land.
And in small pools, where other animals are very scarce, water isopods crawl sluggishly over the muddy bottoms, feeding on dead leaves and other decaying vegetation. These little crustaceans, which look like miniature armadillos when viewed from above, seem to think that February is as good a month as any in which to mate, so females may be found carrying eggs in brood pouches under their legs. They must believe in frequent matings because from February until summer they have a new brood of young every five or six weeks, and the females are always carrying a brood pouch full of eggs or of developing young ones.
Other animals also feel the urge to breed. Yellow perch begin to migrate to their spawning places in shallows along pond and lake shores; skunks and gray squirrels seek their mates; and the great horned owl may be heard courting with loud hoots.
I know of nothing more disturbing than to be suddenly startled by the loud "who, hoo-hoo-hoo, who-who" of this owl, as his cry speeds through the cold, frosty air, breaking the silence of a winter's night with unexpected shrillness. It has an eerie quality, and a suggestion of nameless terror. I wonder if the creatures of the woods experience the same sensation of fear which we sustain when suddenly confronted with danger as this fierce predator announces his presence, for no living thing above ground, except the larger mammals and man, escapes his talons. Even the skunk is not exempt, for this implacable enemy, flitting through the woods silently as a shadow, cares little for the disagreeable consequences of attacking such a pungent animal.
I do not often see the great horned owl but I frequently hear him on winter nights when the lack of food sometimes drives him to visit an isolated farmyard. Never a really silent bird, he is more vocal in January and February, particularly during his courtship. His mating antics are most curious and something to see. He nods his head, flaps his wings, and bows, using, meanwhile, the choicest words of the owl language in his most persuasive manner. If mating occurs early enough in February, the eggs may be laid before the end of the month. Whatever your opinion of the bird, you cannot accuse it of neglecting its young, for the mother sits closely on her eggs during the cold days and long nights and it is not uncommon to find her stolidly incubating under a thick blanket of snow.
As February grows old, melting snows gradually reveal patches of spreading strawberry leaves in fields and meadows and mats of lovely gray reindeer lichen in woods and thickets. When I first saw this lichen it was a summer's day and I wondered how the reindeer could find its stiff, coral-like growth either palatable or edible. But when months later I found it again newly uncovered by snow, soft as a sponge, and exceedingly lovely in its freshness, I saw how easily the reindeer, lemmings, and other cold-climate animals could subsist on it and why the Scandinavians once made bread with it.
The strawberry plants, of interest in the spring when their white flowers cover the ground and even more attractive later in summer because of their red, pulpy berries whose delicate flavor is unrivaled by cultivated varieties, attract us now for the dainty lace bugs which spend the winter beneath the leaves. I suggest you find one of these tiny insects and examine it under a lens. You will be surprised and henceforth you may realize that small things are not always so insignificant as they seem.
Spring is still a month away, yet spring is in the air and signs of it are everywhere. Snow buntings in swirling flocks have begun to move northward along ocean beaches, and the first woodcocks have appeared, though the main flight will not appear until later. The first geese are returning on their spring trip northward and black ducks are winging their way to their breeding grounds. Starlings are beginning to whistle and cave bats, awakening from their winter's sleep, are making short flights in their quarters. But spring will not have arrived until I catch my hot glimpse of blue among the naked branches of a roadside maple. For only with the arrival of the bluebird will spring have come, though my calendar tells me otherwise.
Natural Events in February
The trim leaf-wrapped cocoons of the promethea moth are conspicuous on the naked branches of the wild cherry and sassafras.
Weasels, shrews, and other mammals, not in hibernation, search for food.
Snow buntings, moving northward, feed along the ocean beaches in swirling flocks.
The red berries of the barberry are eagerly sought by wintering soft-billed birds.
Nymphs of various May flies are abundant in swift rivulets and spring-fed brooks.
Gray squirrels use tunnels under the snow when hunting for buried nuts.
Yellow perch begin to migrate to their spawning places in the shallows along pond and lake shore.
During mid-winter thaws, the mourning cloak butterfly may be seen flitting among the trees in sunny glades.
The great horned owl is heard courting with loud hoots. The eggs may be laid before the end of the month.
Naked trees, silhouetted against the winter sky, cast their tracery on the snow-covered ground.
On mild days, snow flies may be found walking over the snow.
Deer nibble twigs and the foliage of evergreens.
Starlings begin to whistle.
The larvae of the dobson fly, known as hellgrammites, may be found in holes and crevices beneath the rocks of swift-flowing streams.
Northward flights of black ducks begin.
Water isopods begin to breed. Females have eggs in pouches under their legs.
Cave bats make short flights in their winter quarters.
Two-lined salamanders are active in swift shallows.
Various insects hibernate in the leaves of pitcher plants.
Brook leeches may be found clinging to the undersides of rocks in swift riffles.
Shelf brackets, in greens, reds, and browns, encircle old stumps or, stiff and white, stand out from crumbling or fallen moss-grown boles.
The larvae of the Baltimore checkerspot butterfly winter in silken tents on the withered stalks of members of the figwort family.
Scuds swim in spring-fed streams.
The pitch pine, despite its scraggly appearance, reveals a picturesque ruggedness beneath its burden of snow.
Dainty lace bugs find refuge from the winter storms under spreading strawberry leaves.
The first woodcocks appear; these are occasional individuals, the main flight still a month away.
Bristleworms are active in ponds and streams.
Spruces and hemlocks, their white robes glistening in the February sunshine, provide a decorative background for winter's stage.
On sunny days, diving beetles frequently rise to the surface of ponds and streams.
Brown creepers on the trunks of trees industriously search for insects.
Gray squirrels mate.
In patches free from snow, the reindeer lichen carpets the forest floor with a gray corallike growth.
On warm days gnats fly forth in small swarms or by thousands.
Half grown caterpillars of the brown-tail moth pass the winter in small, firm-webbed nests of silk and leaves on the tips of twigs.
The dried remains of the flower-gall persist on the naked branches of the white ash.
The black knot stands out on the naked branches of the choke cherry.
The scarcity of other food drives chickadees, blue jays, and other wintering birds to feed on sumac berries.
The first hardy flocks of geese return on their spring trip northward.
Kinglets feed unconcernedly, though the north wind howls and pine branches groan beneath heavy burdens.
Porcupines feed on the bark and leaves of evergreen trees.
Meadow mice scurry about their runways beneath the snow on trips of exploration.
Crossbills feed on the seeds of the pine, which they pry loose with their curiously crossed bills.
Evergreen plants add a touch of summer to the winter scene.
Oak apples are conspicuous on the leafless branches of oak trees.