| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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Naturalist's Almanac What to look for this Spring April
Known as the "roadrunner of the lizard world," and cursed by herpetologists for its wariness and speed, the western whiptail wakes from winter dormancy this month. Juveniles appear first, soon followed by 13-inch-long adult males eager to establish mating hierarchies. Last April, while photographing wildflowers in Joshua Tree National Park, I ran into two males rolling around in the dust. Each had a robust grip on the other's head. Though panting and bleeding, neither was willing to part ways for a good 15 minutes. When one finally broke free, he ran as far into the desert as he could. The victor won the right to mate with females as they emerged from the desert's soils. Whiptails tolerate heat extremely well: even during scorching summer months, they remain active for over 90 percent of the day. These agile hunters find much of their insect prey with the help of a keen sense of smell. They are the only widespread whiptail species in California, occurring in arid and semi-arid habitats the length of the state.
The northward migration of gray whale mothers and their newborn calves this month is fraught with peril, but none greater than the threat of attack by orcas during the crossing of Monterey Bay. A spate of killings last spring generated a considerable amount of media coverage (see California Wild, Fall 2004) and may represent a relatively new occurrence on the Pacific coast. Scientists and curious onlookers alike will be on the alert this spring for a repeat performance. Nowhere else along the coastal migration route do whales and their vulnerable calves cross such open water. The bay's deep canyons make it easy for orcas to launch a surprise attack. Despite their considerable advantage in size and weight, gray whales are little match for the ferocious assaults of four-ton killer whales working in cooperative hunting packs. Visitors may have a chance to view this phenomenon on one of the many trips led by the Monterey Bay Whale Watch (831) 375-4658.
The murky waters of the Colorado River hide one of California's most distinctive reptiles. The spiny softshell turtle is covered with leathery, sandpaper-textured skin. A long, tubular snout gives it the appearance of a tiny alligator. They grow up to two feet across. During May, males go on the prowl for mates. Desperate bachelors can be observed poking their snouts under the shells of basking companions, looking for a female. Other males and unreceptive females turn and bite the intruder, marking him with bloody wounds characteristic of softshell breeding season. After an underwater courtship, females crawl onto sunny riverbanks to lay the first of several clutches of eggs.
If chaparral is California's signature plant community,
then the state's most characteristic plant would be chamise. This
species is unbelievably abundant and widespread on countless dry slopes
west of the Sierra Nevada. The Spanish even coined the term chamisal to
describe the distinctive appearance of hills cloaked with this brush.
The plant's superb adaptations to drought and fire allow it to dominate
a vast acreage. For example, its evergreen leaves begin photosynthesizing
within minutes of rainfall. Its dual root systems capture both surface
moisture and deep water sources. In addition, its leaves hoard water in
the face of brutal sunlight. By growing in dense stands and emitting combustible
gases at the approach of fire, chamise actually encourages stand-replacing
fires. Given a clean slate, it will sprout from its roots and outdistance
potential competitors. By early summer, however, it is well into another
part of its life cycle: reproduction. It produces huge numbers of tiny
white flowers that are faintly reminiscent of roses under a hand lens. June
Though everyone with a backyard is familiar with the handiwork of the broad-footed mole, amazingly little is known about the ecology, behavior, and reproduction of this common animal. As a result, its life underground remains shrouded in mystery. If its close relatives are any indication, this widespread California mole gives birth to litters of two to three young in early spring. Pregnant females construct a nursery under a large mound of dirt (called the fortress) in an area of moist, loosely packed soil. The nest's inner lining will be made of fine, dry grasses tucked into a ball of wet, green grasses that generate heat as they decay. About a month after birth, the young moles make their first foray from home, though they won't travel further than a few dozen yards. Biologists have encountered many of these young animals in June just starting to dig their first tunnels in search of earthworms and insects. Hungry owls and domestic cats and dogs on the prowl make burrow building a high priority for juvenile moles.
In the sliver of southeastern California occupied by the Sonoran Desert, the saguaro cactus is midway between flowering and setting fruit. Three inches wide and a waxy white, saguaro flowers have all the features of blooms designed to attract bats but instead are pollinated by bees and doves. This curious turn of events leads some scientists to wonder if saguaros are in the early stages of an evolutionary shift in pollinators. While some saguaros are still producing these fragrant blooms in early June, the first bright red fruits are already starting to ripen by the end of the month. Loaded with succulent juices, saguaro fruits may be the only moist foods in the neighborhood. This makes them a staple for many animals during the hottest, driest season. In return, doves and woodpeckers that eat saguaro fruit will carry the seeds to new sites. Sadly, the majority of California's saguaros were drowned in the early 1900s, when Laguna Dam was built on the Colorado River. With them went the primary habitat for gila woodpeckers, gilded flickers, elf owls, and many other imperiled California species. Saguaros grow very slowly (most don't begin producing their characteristic arms until about age 100), so it'll take awhile to know if the saguaro stands can return to their former glory.
David Lukas leads natural history tours and programs in the Bay Area. He can be reached at davidlukas@earthlink.net |
