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The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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Naturalist's Almanac What To Look For This Winter
December
January
February
David Lukas leads natural history tours and programs in the Bay Area. He can be reached at david@naturalists-in-action.com. |
On
coastal beaches, where life is as stable as a storm-tossed piece of driftwood,
a few hardy plants struggle to survive between two opposing forces. On
one side lie the densely vegetated dunes of the upper beach, where competition
for scant resources is fierce, and on the other the crushing might of
winter waves. Pocketed in the space between is the resourceful sea
rocket. Each of its missile-shaped fruits is divided into two
components. The larger outer part drops off in late November and waits
to be carried to new destinations by the high waves of winter storms.
The smaller basal portion lingers on the plant, dropping off later to
germinate in home soil. This way, the plant doubles its chances of establishing
offspring along the uncertain world at the ocean’s edge. Since its
introduction from Europe in 1935, the sea rocket has expanded its range
from San Francisco to British Columbia and Baja.
Chilly
winter rains prompt many animals to head for shelter, but are also the
siren song calling forth sleepy California newts. Along
the western Sierra Nevada and the length of the coast, these gentle creatures
appear overnight from underground hiding places and begin waddling towards
breeding ponds and streams. Beginning in December, males congregate at
favored sites to await the arrival of females. Courtship involves a male
clasping the female in his arms and softly rubbing his chin on her nose
for an hour. When the time is right he moves to one side and deposits
a gelatinous sperm packet on the mud. She picks it up with her cloaca
in preparation for laying eggs. Because each female mates only every other
year, males outnumber females at breeding sites and may surround the ladies
in frenzied courting clusters.
Imagine
how it would feel on a cold, rainy, or snowy day to retreat into a cozy
nest of delicately shredded fibers where you would be safe and warm. In
your nest you’d have a stockpile of seeds and nuts to nibble on
between naps, and occasionally you’d wander out on short foraging
runs to check the weather. Such is the winter world of the deer
mouse, California’s most abundant and widespread mammal.
Despite being eaten by snakes, owls, and weasels, deer mice flourish because
they reproduce several times per year and occupy every terrestrial niche
from treeline to ocean beach. In such numbers these small native mice
exert a profound influence on ecosystem dynamics.That’s especially
true in spring, when they emerge from their nests and feast on the grubs
and caterpillars that harm forest plants.
Fly
agarics appear out of the forest gloom like hallucinogenic thunderbolts.
You can hardly believe you’re actually seeing one of those dazzling
red mushrooms with white-spotted caps caricatured on posters and as plastic
lawn ornaments. They are acually fairly common in the conifer and madrone
forests in the Sierra Nevada and coast ranges of California, and widespread
in Europe and Asia. As one of the toxic amanita mushrooms, the fly agaric
is shunned by gourmets. But before alcohol was widely available, this
mushroom was reportedly an important intoxicant, and a good case has been
made for it being the Soma plant of the sacred Hindu RgVedas texts. However,
their toxicity ranges so widely from ’shroom to ’shroom and
population to population that ingesting one can be a fatal gamble. It’s
better to admire these fungi from afar.
On
a warm, early spring day you’re likely to see hairy bumblebees
meandering along in heavy flight. Though bulky and apparently clumsy the
common yellow-faced bumblebee and its kin use a sophisticated strategy
to survive. Unlike smaller bees that wait to come out in late spring,
bumblebees retain heat with their furry bodies. The warmth enables them
to fly on colder days and visit early-blooming spring wildflowers. Many
of these flowers won’t release pollen from their anthers unless
triggered by larger bees. Upon landing on these flowers, a bumblebee vibrates
its wings at a special frequency that shakes pollen free—a process
called “buzz pollination.” That buzz is audible—hold
still and listen if you can. In exchange, bumblebees receive rich nectar
meals not available to insects trying to steal a snack without triggering
a pollen release. 
Although
rarely seen except at low tide, the red sea urchin is
very common along rocky stretches of the California coast. Looking like
seven-inch space pods with spines, these creatures spawn from February
to March. While exact counts are difficult to make, it’s known that
a related species may produce 20 million eggs per year. With these numbers
it’s not surprising that red sea urchin populations have soared
in the absence of predators such as sea otters, and in some areas have
decimated vast kelp beds with their grazing. Point Lobos State Reserve
(831-624-4909) tidepools offer chances to find both red and purple urchins.
After
a midwinter visit to the warm bays and lagoons of Baja California’s
Pacific coast, gray whales begin swimming northward in
late February and early March. This aspect of their annual migration is
easily overlooked; the first waves of northbound juveniles and nonbreeding
adults remain well offshore as they pass the California coast. It is much
easier and more enjoyable to watch females migrating with newborn young.
These pairs meander playfully along our shore in April. But don’t
underestimate the urgency of early migrants as they head back to arctic
feeding grounds. Three to five months without food will push even 30-ton
whales to the edge of survival.