California Wild Winter 2004 - Naturalist's Almanac

The Magazine of the CALIFORNIA ACADEMY OF SCIENCES

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CALIFORNIA WILD

NATURALIST'S ALMANAC

What to Look For This Winter

David Lukas

January

Obscure and stinky, the slink pod (Scoliopus bigelovii) of the northern California coast exemplifies how a small understory flower can survive in the shade of mighty coniferous forests. With two oddly mottled eight-inch-long leaves poking from the forest duff, this inconspicuous cousin of the lily produces several long-stalked flowers that reek of something foul. There just aren’t enough large pollinators like bumblebees around in the middle of the rainy season, so hordes of tiny gnats swarm the smelly flowers instead. Blooming in winter lets the plants take advantage of the scant sunshine available before the canopy closes over with spring leaves. This schedule also allows their seeds to ripen in early summer, when many other species are just starting to flower. In summer, slink pod stalks heavy with fruits will bend to touch the ground. Ants often raid the seeds and carry the spoils to their underground nests. The reward? Each seed comes with an oily nodule called an eliaosome that ants love.

The San Francisco Bay Flyway Festival comes to Mare Island January 23-25. See the crowds of shorebirds, hawks, and waterfowl that migrate here each winter. 707-557-9816.

February

For birds that feed on large flying insects most of the year, winter is a lean season. Acorn woodpeckers make it through the coldest months by hoarding ripe acorns in carefully guarded “pantries.” Since oaks don’t produce acorns in winter, woodpeckers must collect them as they ripen throughout summer and fall. The birds tap the acorns into individual divots pecked into tree trunks and other woody surfaces. These woodpeckers have been known to cache up to 50,000 acorns at a single site. But storing the acorns is only half the battle; in winter, the woodpeckers spend nearly every waking minute guarding their granaries from other hungry acorn-eaters. So arduous is this task that the birds must live in cooperative social groups. This way they can take turns chasing away a steady stream of thieving nuthatches, titmice, jays, and squirrels demanding a piece of the stash.

Residents of the northern California coast are familiar with the ubiquitous yellow-spotted millipede. Roaming a wide variety of forested habitats on wet days, this black millipede with yellow spots along its flanks is also nicknamed the black princess. They are thought to play a critical role in breaking down conifer needles. Reaching densities of 20-90 individuals per square meter, these millipedes may consume more than a third of the conifer needles that fall to the forest floor. Their bodies convert the needles into frass that decomposes readily and releases large amounts of nitrogen into the ecosystem. Such a common and openly visible organism would make an ideal prey item for many predators—except that millipedes under threat protect themselves with poisonous hydrogen cyanide. If you pick one up, you’ll immediately note a pungent, bitter, almond-like smell on your fingers. The stench will probably make you want to put the animal back down immediately, just as it intended you to do.

March

What a relief it is when the rains arrive again in southeastern California. That’s especially true if you’re two inches long and have been waiting underground for seven to ten months siphoning stored water from your extra-large bladder to stay alive. Parched doesn’t come close to describing how you feel after losing forty percent of your body mass in water. But one night the ground starts trembling with the rhythm of heavy raindrops, and you awake ready to scrabble through the desert sand to the surface. For the tough little red-spotted toad, this is the cycle of life. At the top of a toad’s short list of post-emergence activities is settling its hind end in a pool of water. A patch of thin, capillary-rich skin absorbs moisture fast, allowing the toad to rehydrate. Filling the night air with reverberating trills and promptly mating come next.

Pop quiz for bird enthusiasts: What bird is nicknamed the teeter-bob or tip-tail? In case you need a few clues, it spends its winter living along rocky shorelines of the California coast and inland along rivers of the Central Valley. Stiff, shallow wingbeats send it gliding briefly low over wetlands to settle in a new location. Nearly always found alone, it is one of very few birds in which females are larger, more dominant, and fight aggressively for access to males. Successful females will mate and lay eggs with up to four different males, leaving them to tend the eggs and chicks. By now you’ve surely guessed that our bird is the spotted sandpiper. March is an excellent month to find them along the coast before they start heading back into the mountains to breed along fast rocky streams.

Desert rains don’t just trigger toads, they also rekindle life in the creosote bush, one of the most widespread plants of the California desert. Evergreen and growing up to six feet high, these dark green shrubs bear clusters of tiny resinous leaves at the ends of otherwise bare twigs. Following winter and spring rains, small yellow flowers appear among the leaves. These attract a profusion of insects, including 22 species of bees that visit only creosote flowers. Animals from creosote katydids to black-tailed jackrabbits also rely on the plant, making it a keystone species in its ecosystem. But creosote seeds that fall near their parents don’t fare as well. The plants produce germination inhibitors that prevent competitors from growing in the vicinity. Such unlucky seeds may have to wait awhile for a chance to sprout; the root systems of creosotes don’t die as they age, but keep cloning new stems for up to 11,000 years.

Deer In Winter

The deer of our imagination graze in lush green forests and meadows. But where do deer go when deep drifts of snow cover this habitat? They descend from the hills until the white fluffy stuff no longer buries leaves and ground cover. Winter foraging areas and the routes deer use to reach them have become so well established over the centuries that biologists have mapped them out. These migration routes are not narrow paths but rather broad corridors that may be 30 miles long and five miles wide. They end in oak woodlands where deer paw the ground in search of rich, nutritious acorns. In late winter, they switch to eating newly emerging grasses and forbs. Range and migration corridors are perhaps most critical for deer survival in winter, since this is the leanest season. All too often, humans unwittingly plan building projects right through the hearts of these winter ranges. When a road is constructed across a migration corridor, large numbers of deer are needlessly killed each year.