California Wild Fall 2002 - Naturalist's Almanac

The Magazine of the CALIFORNIA ACADEMY OF SCIENCES

Naturalist's Almanac

David Lukas

OCTOBER

Cumbersome would be a good word to describe what it’s like to carry 30,000 barbed quills on your back, but it may not be a strong enough way to describe the delicate art of porcupine procreation. Mostly solitary, these large, cautious rodents mark the transition to winter with a burst of reproductive activity from October to November. During brief encounters between males and females, or between males vying for a female’s attention, these normally silent animals utter a bizarre variety of what have been called “love songs” consisting of squeaks, moans, whines, wails, grunts, and coughs. Prior to copulation, a male performs a three-legged walk while holding his genitals with a forepaw, rubs his genitals on rocks and branches, and then tries to heighten the amorous mood by standing upright and wetting the female’s belly with urine. From this standing position, the pair sometimes tumbles over, leading to mistaken assumptions that porcupines mate lying down facing each other. After copulation, a tricky affair with quills, the female quickly loses interest in the male and wanders off to spend the winter sleeping in treetops and nibbling on the bark of conifers.

The scarce Townsend’s long-eared bat also waits until early winter to mate. After spending a mostly solitary summer, males gather at hibernation sites frequented by groups of females. While females quickly enter into a winter-long torpor, males choose warmer niches that enable them to rouse repeatedly and even fly occasionally about the cave or its entrance. During the first three weeks of October, males use this mobility to mate with dormant females, an activity that continues sporadically until about February. Females subsequently store sperm through the winter and fertilize their single eggs in early spring. Long-eared bats are highly susceptible to human disturbance within their roosting caves, and may readily abandon a traditional roost site after a single human disturbance—a factor has contributed to an alarming decline in this and other bat species.

This is the month of prime salmon viewing as the fish move from the ocean into freshwater streams to lay their eggs on clean gravel bars called redds. For each hundred eggs laid, only one survives to reach adulthood. But of those that live, 90 percent return to spawn within 100 yards of their birthplace. This incredible drive to return to one’s birthplace has long impressed humans. Today, the people lining riverbanks to watch salmon spawning sometimes outnumber the fish. Popular sites include the Iron Gate Salmon and Steelhead Hatchery on Bogus Creek (just below Copco Lake on the Klamath River), and the Nimbus Fish Hatchery along the American River in Rancho Cordova.

NOVEMBER

With the onset of winter’s first rains, newts and salamanders become active after a long summer dormancy. Inconspicuous among this lot is the worm-like California slender salamander. Within weeks of emerging from their summer hideouts in deep crevices and niches, slender salamanders mate and lay moist eggs under rocks or other surface objects or in underground cavities. Though each female typically lays about 10 eggs, batches of up to 74 eggs have been found, suggesting that numerous females may nest together, depositing their eggs at a single site. After approximately two months, half-inch-long hatchlings emerge.

After just five years, the Central Valley Birding Symposium has earned a reputation as one of the premier birding events in the western United States. Based in Stockton, the Symposium combines a rich array of field trips, displays, vendors, and lecturers. Field trips to the Central Valley’s foremost bird refuges make each afternoon a host of exciting stories and lengthy bird lists to be shared and discussed. Late-afternoon events include slide shows and talks by well-known speakers that have included, in years past, Kenn Kaufman and Pete Dunne. This popular gathering usually fills to near capacity so early registration is highly recommended. This year’s Symposium will be held November 21-24, 2002. Details are available at www.cvbs.org.

DECEMBER

Even though western pond turtles may remain active year-round in southern, lowland regions of California, this is hardly an animal associated with winter. In fact, most turtles spend the season buried in the muddy bottoms of large rivers and lakes. A flurry of reports, however, suggest that hatchling turtles may also have this odd habit. Rather than digging out of their dry subterranean nests in late summer and moving to nearby waters to hibernate with adults, as previously thought, they appear to remain underground after breaking out of their eggs, and emerge in spring. So, if you’re taking a winter walk within several hundred feet of a lake or river shoreline, tread softly—you may be walking over the tops of sleeping baby turtles.

Winter’s first big storms bring not only nourishing rain but also an onslaught of large waves that sluice away the broad, lazy beaches of summer. All along the coast, turbulent waves arriving in quick succession pick up sand particles from the berm (the visible portion of the beach) and carry the particles offshore, to be deposited on a bar (an underwater ridge paralleling the coastline). These ridges may be revealed at the very lowest tides. In the process, a broad, flat beach can be transformed into a narrow, steep, and sometimes rocky strip. At Carmel Beach, 200 feet of gently sloping sand is removed each winter, to be replaced by gentler waves the following spring.

Food Fit For The Birds

One popular wintertime activity for nature enthusiasts is feeding backyard birds, but few people understand the dynamics and ecology of this activity. A common misconception that feeding wild birds makes them dependent on humans, buut the truth is that wild birds cobble together a feeding routine based on numerous "resource patches." Dependence on any single patch, including your feeder, is strictly avoided. While small birds spend over 80 percent of their day looking for food, and need to eat every two to three seconds during the coldest days, a 1992 study by Margaret Clark Brittingham of the University of Wisconsin found that chickadees obtained up to 80 percent of their daily energy from the wild, even with unlimited access to bird feeders. Nor do you have to worry that birds will suffer nutritional deficiencies if you put out just one type of seed, because birds instinctively round out their diets by seeking a variety of foods. The key for feeding birds during winter is providing clean, fresh seed, because birds learn to avoid feeders or backyards where they have had poor dining experiences.

David Lukas is a freelance writer living in California.