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CALIFORNIA WILD

Naturalist's Almanac

What to Look for This Spring

Liese Greensfelder

April
On the shrub-scattered plains of northeastern California, sage grouse flock to their ancient mating sites in the spring. As many as 70 cocks gather in early morning rituals, where they swagger and battle like gladiators in a coliseum. A victorious male can end up mating with as many as three quarters of the hens on site. As they fan their spiked tails, the cocks puff muscular neck bags into huge, resonant pockets that produce their famed and eerie vocalizations. Researchers recently discovered that the birds have an uncanny ability to project each portion of their song in a different direction. Cooing sounds are sent forward, “pops” are beamed either straight ahead or to the side, while whistles are emitted sideways or straight back. Like a lighthouse beacon, these focused calls travel up to twice as far as more spread-out sound. The strategy may help the big guys target their gals while avoiding detection by predators.

Breathtaking wildflower displays blanket California’s hillsides in the spring. To view some of the state’s rarest flowers, visit areas dominated by serpentine soils, which derive from serpentinite, rock from the Earth’s mantle that pushes to the surface along geologic faults. Laden with unusually high amounts of magnesium, nickel, and chromium, but short on calcium, serpentine soils have spurred the evolution of more than 200 species unique to California, such as California vervain, Presidio clarkia, and Tiburon mariposa lily. Impressive stands of serpentine flora can be found at Jasper Ridge Preserve in San Mateo County, Ring Mountain Preserve in Marin County, Pine Hill Ecological Preserve in El Dorado County, on Figueroa Mountain in Santa Barbara County, and throughout the Klamath-Siskiyou region.

Bay checkerspot butterflies emerge from pupation in early spring after winter rains have greened their habitat on the hills of the San Francisco Peninsula. Mating flights from March to May are timed so that larvae will hatch from eggs before summer days dry out succulent host plants. Larval checkerspots prefer dwarf plantain, a small plant that grows best on serpentine soils. But in recent decades, alien species that normally can’t tolerate serpentine’s chemical mix have invaded the plantain’s territory, stifling the smaller plant under dense foliage. The reason? Nitrogen from auto exhaust has enriched the soil, favoring aliens over natives.

May
Great blue heron and great egret chicks are learning to fly this month at Audubon Canyon Ranch just north of Stinson Beach in Marin County. A short walk up a steep trail rewards visitors with spectator-seat viewing of the birds’ nests scattered among the canyon’s redwoods and Douglas fir like ornaments on a Christmas tree. The ranch is open to the public on weekends from 10 a.m. to 4 p.m., March 17 to July 15. Limited visiting hours Tuesday through Friday by appointment only (415) 868-9244.

Some of the year’s lowest tides will occur during the early morning hours of May 24-27 and June 22-24. Grab your sneakers (or waders) and head to the coast to explore the riotous biological diversity of the intertidal zone, where it’s not unusual to find specimens from as many as seven or eight phyla clinging to a rock face no bigger than a roadmap. To find the richest pools, stay away from beaches, where surf-churned sand scours the rocks clean. Tidepools from Alaska to San Diego host many of the same plant and animal species, as weather and water temperatures are monotonously alike along the Pacific coast. Check local tide tables for exact times of tidal lows, or at http://co-ops.nos.noaa.gov/tpred2.html#CA.

June
Though Sutro Forest below Twin Peaks in San Francisco is a jungle of aggressive alien plants such as eucalyptus, English ivy, and Scotch broom, a pair of red-tailed hawks have made it their home. Red-tails tend to reuse a nest year after year, adding new sticks to these tangled aeries built in the forks of tall trees or on cliff ledges. If the Sutro pair nests successfully again this year, the brood should make their public debut in late June, hanging out in the upper branches of the eucalyptus trees at the edge of the forest for days. Stroll along upper Stanyan Street and listen for the chicks’ incessant, whistling cries as they harass their parents for food. When the fledglings finally screw up the courage, they’ll plunge into the air above the city’s streets and learn their soaring skills on the fierce winds blowing in from the Pacific.

Female western pond turtles plod away from their ponds, marshes, and streams sometime between May and July to lay clutches of 1 to 13 eggs. Although she may wander more than a mile in search of a suitable nest site, a female typically buries her eggs in well-drained soil close to the water’s edge. When the young hatch three to four months later, they head back to the water, where they often end up as snacks for bullfrogs and bass, introduced species whose appetites are tipping various natives toward extinction. Once found throughout most of the state, the turtles are rapidly losing ground to alien species and habitat destruction. A pond turtle spends much of the day basking in the sun, maintaining its body temperature. But the moment it senses a predator coming, the canny creature drops from its log or pondweed perch and disappears under the water. If you hope to see a pond turtle in the wild, get in the habit of sneaking up on bodies of water

Friendly Fire 
Spring and fall are the seasons for prescribed fires in California’s forests. These carefully managed burns reduce woody debris, providing a safeguard against catastrophic wildfires. But good days for prescribed fires are often few and far between. Soils and fuels can’t be too wet or too dry, and wind and humidity forecasts need to be just right as well. In the spring, forest litter and soils are usually much damper than in the fall, suggesting that spring fires can be safely kindled in a broader range of weather conditions. Yet fire managers have reason to be even more conservative when “prescribing” spring fires. These fires must burn slow and cool to avoid damaging seeds and shoots of sensitive annual plants, the swelling buds and new growth of perennials, and the tender roots of trees that grow close to the soil surface. Even the trees themselves are at greater risk in the spring, for once their sap begins to rise, they’re much more susceptible to heat injury. Despite these drawbacks, until a century of accumulated debris is cleared from the woods, spring fires will remain valued weapons in a fire manager’s arsenal.

Spring 2001

Vol. 53:2