Tracks in the snow, glistening icicles, a deer nibbling on
low branches, these are only a few of the many pleasures of
winter exploring. But if you look and listen just a bit
more closely, you’ll also discover that the frozen world is
full of less-than-obvious natural wonders that most of us
don’t see simply because we don’t take the time. Here are
some examples:
A Touch of Velvet
Standing in stoic defiance of icy temperatures that would
flash freeze most other fungi, the tawny-capped winter
mushroom, Flammulina velutipes, fruits in the dead of winter even in the most
northern states, giving heart to winter-weary shroom
hunters who are in search of something, anything, to put in
their gathering baskets.
Also called the velvet foot mushroom for its soft, fuzzy
base, this is the wild version of the commercially
cultivated enoki mushroom. Enokis, however, are grown in
sawdust in the dark, resulting in light-starved mushrooms
with long, thin stems and tiny caps that look more like
bean sprouts than fungi. Wild winter mushrooms have thick
stems and wide, fleshy caps.
Watch for these hardy survivors standing in little clusters
at the feet of elms and other woodland trees. But unless
you’re an expert, don’t even think about eating them, they’re
easily confused with an aptly named look-alike, the deadly
galerina.
Hoot Suitors
At dusk, if you think you hear the soft cooing of a
mourning dove, listen again more carefully. It may be the
similar-sounding but distinctive hoo-hoo hooooo hoo-hoo of
a great horned owl.
Known as the feathered tiger of the air, great horned owls
are ferocious predators of anything and everything they can
get their talons on, from beetles, frogs and fish to
rabbits, raccoons, porcupines and domestic cats.
But starting in December, great horned owls turn their
attention to mating and fill the evening air with
come-hither hoots and other vocalizations. If you’re lucky,
you might spy a pair flirting at twilight in a courtship
ritual that includes spreading their wings, bowing their
heads and clicking their beaks. By late January in most
areas, females sit silently atop eggs, a pair,
usually, that will hatch a month later, in time for the
young to mature enough to feed on springs fresh supply of
infant animals. Look for great horned owls in the abandoned
stick nests of crows or hawks.
Woolly Brrrrr
Sift beneath leaves or peek under a snow-dusted log, and
you may discover a curled-up, apparently lifeless
black-and-brown-banded caterpillar, the famed woolly bear
said to predict the severity of winters by the lushness of
its fuzzy coat. Don’t give it up for dead just yet, though.
Like a variety of other overwintering creatures, woolly
bears produce an internal antifreeze called glycerol that
protects their vital organs from subfreezing temperatures.
But more than simply preventing freezing, the woolly bear
is able to endure the formation of ice crystals in its body
by limiting the growth of ice to the spaces between tissue
cells. Meanwhile, it produces sugars that keep its blood
and cellular water in liquid form. Come the thaw in early
spring, the frozen bear will rouse itself, find a sheltered
place on which to spin a cocoon and pupate. In early
summer, a handsome Isabella tiger moth (Pyrrharctia
isabella) emerges.
Woolly bears are only one of dozens of freeze-tolerant
species, including some turtles as well as many insects in
either the adult, larval or pupal stage. Perhaps most
astounding is the wood frogs ability to withstand being
frozen without (ahem) croaking. In winter, its entire
abdominal cavity fills with ice, completely encasing all
its internal organs. Its blood stops flowing; breathing and
heartbeats cease; its eyes turn white because the lenses
freeze. And so the frog-cicle remains until the thaw, when
spring quite literally returns to its step.
A Hole in the Snow
Look for a small hole in the snow at the edge of a meadow.
Chances are its the exit or ventilation hole of a field
mouses tunnel. On unseasonably mild days, field mice might
emerge to forage for seeds or bark. But for most of the
winter, they live beneath the surface in the snug
snow-covered environment of thick grass, leaf litter and
crisscrossing tunnels that scientists term the subnivean
zone. Here, regardless of chilly winds and subfreezing air
in the harsh world above, temperatures seldom dip below 32
degrees.
Safe from owls and other predators, nourished by roots and
grass, and kept warm by the earth itself and an insulating
snowflake blanket, these rodents prosper in winter just as
well as they do in any season, with females sometimes
producing as many as five young per month. The females
among those babies, in turn, start producing litters of
their own one month later. This ongoing population
explosion produces a spring smorgasbord of bite-size
protein for foxes, coyotes, hawks, snakes and other
creatures, and fuels the reproductive cycles of those
creatures, ensuring the perpetuation of a healthy
ecosystem.
If you find a mouse hole in the snow, take note of its
location and come back in the spring. Part the grass, and
you’ll discover an elaborate maze of pathways pummeled
smooth by countless wee footsteps.
Some Gall!
As you venture across winter fields, watch for the tall,
dried stalks of goldenrod, one of North Americas most
widespread weeds. Chances are you’ll spy at least one stalk
with an odd round swelling about an inch in diameter: a
gall formed around an invading insect. Using a pocket
knife, carefully cut open one of the swellings. Inside,
you’ll discover a hard, pale worm, probably the larva of a
goldenrod gall fly.
In late spring and early summer, adult gall flies, which
are less than a quarter inch long, have clear black-banded
wings and prefer walking to flying, lay eggs on the tips of
emerging goldenrod stems. About 10 days later, the eggs
produce larvae that bore into the stems, usually one larva
per stem. The little worms chewing action and saliva
stimulate the growth of extra plant tissue around it,
creating a pithy, vegetative sphere that provides both
shelter and food. In autumn, before going into dormancy,
the larva burrows outward, preparing an exit tunnel that
stops just short of breaking through the galls surface.
Then the larva retreats back to the galls center, where it
remains until it pupates and turns into an adult fly the
following spring.
If you remove the larva and warm the immobile creature in
your hand for a minute or two, itll come out of its
cold-weather stupor and wiggle. No wonder winter anglers
like finding goldenrod galls: live bait! Downy woodpeckers
are fond of goldenrod galls, too, and use their tiny,
pointed bills to bore into the spheres to extract the
morsels inside.
Amazing Snowflakes
Look upward as snowflakes drift delicately from the sky. Go
ahead and stick out your tongue, can you catch one?
Aristotle had it almost right when he wrote, When a cloud
freezes, there is snow. A snow crystal is born when a water
droplet condenses and freezes around a bit of dust or ice
inside a cold cloud. The infant crystal, a few thousand
water molecules held by electrical charge in the shape of a
six-sided plate or disc, immediately begins to fall. Its
the start of a two- to six-mile tumble to earth, a journey
that may take some two hours and perhaps cover hundreds of
horizontal miles.
As the crystal tumbles, it grows by drawing trillions of
vapor molecules out of the air and onto its surface like a
magnet. The molecules flow across the crystal and freeze,
locking together in any of the myriad patterns that we
associate with snowflakes. But the atmosphere is a
turbulent place, and a snow crystal is a delicate wanderer.
With each small variation in air temperature, with each
flutter of wind, the crystal changes shape. A hexagonal
plate may sprout fernlike projections; a star may suddenly
lose its points. Or the crystal may collide with others and
shatter, seeding the air with particles around which more
snow forms.
But under most conditions the crystal, sweeping the air of
water molecules, growing larger and heavier, eventually
catches in a ball of other crystals, a snowflake. By
definition, a snowflake is not a single crystal, but two or
more stuck together. Finally, it floats gently to
earth, if, that is, its not snagged at the last second by a
snow-loving human with an upturned face and an outstretched
tongue.
