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Mount Diablo Western Toad by Joyce Gross A Preliminary Survey April 1, 1998 By Chris Brown, US Geological Survey, Western Ecological Research Center - San Diego Field Station [Public domain], via Wikimedia Commons In April 1998 I photographed Bufo boreas (western toads) breeding and laying eggs in Little Pine Creek. Of the approximately 20 toads present, females predominated. My previous experience observing amphibian breeding congregations indicated that this was unusual--normally there are more males than females--but I didn't realize how unusual until Bruce Waldman, a herpetologist at the University of Canterbury, New Zealand, saw my photos. Bruce also pointed out that many of the eggs I had photographed were irregularly shaped and not viable, probably "old" eggs, ovulated a week or more prior to actual oviposition. Bruce and I monitored Little Pine Creek in the spring of 1999. Toads always return to the same locations to breed. However, we saw no evidence of reproductive behavior. We found no toads, no eggs, and no tadpoles. Amphibian population declines have been occurring with alarming frequency all over the world during the past few years. There are many possible causes, including pathogenic organisms (e.g. chytrid fungi), high UV-B radiation, exotic predators, and habitat destruction. One of the least understood possible causes is pollution by pesticides, herbicides, and residues of commercial plastics. These compounds are similar in chemical structure to estrogen and other reproductive hormones. Thus it is feared that even at very low concentrations, which may pose no toxicological risk to organisms, these chemicals may mimic female hormones and disrupt normal endocrinological processes. The result might be altered reproductive timing that could contribute to reproductive failure. Of course in this case the reasons for our observations may be completely unrelated to the causes about which we are speculating. In 2000, we received a permit from the park to study the toads and test a few if we found evidence of reproductive abnormalities. I visited the park twice a week from February through June. I found normal breeding activity, resulting in small toadlets by June, in two locations in the park: two miles away at the pond off the Bruce Lee trail in Mitchell Canyon, and two miles in the other direction in a cattle pond near China Wall. At Little Pine Creek there was once again no evidence of reproductive behavior. I found two juvenile toads, but no adult toads in or near the creek, and no eggs and no tadpoles. What happened to the adult toads in the vicinity of Little Pine Creek in Mt Diablo State Park remains a mystery. http://amphibiaweb.org BACK TO LIST

Wildflower Mount Diablo Streambank Springbeauty Scientific Name: Claytonia parviflora ssp. parviflora Family: Montiaceae (Spring Beauty Family) Blooms: March Color: White Annual herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Daniel Fitzgerald Flower detail Daniel Fitzgerald Full plant Daniel Fitzgerald

Tarantula Time by Ken Lavin Fall is Tarantula Time on Mount Diablo October 1, 1998 Ken Lavin Autumn is a delightful time to hike the golden hills of Mount Diablo. But unsuspecting hikers are often startled to find themselves sharing the trails with some rather formidable eight legged walking companions! "What are the critters doing?" "Where are they going?" "Will they hurt me?" These are the common questions park staff and park volunteers must answer this time of year. Fall is tarantula time on Mount Diablo. Mount Diablo's tarantulas (Aphonopelma sp.) have long inspired fear and fascination. One 19th century visitor described our local tarantula as "attaining the size of a small bird, possessing fangs the size of a rattlesnake's, and delivering a bite generally considered fatal!" In reality, the tarantula is one of Mount Diablo’s most innocuous animals—a terror to small insects and not much else! Outside of horror movies, no person has ever been killed by a tarantula. Tarantulas have very small venom glands and the bite of our local tarantula is no more painful that a bee sting. Harmful spider bites generally come from poisonous spiders that are too small to notice. The tarantula, being so conspicuous, gets the blame. For example, in Renaissance Italy, the bite of a tarantula was thought to cause convulsions. The only known treatment was to sweat the poison out by frenetic dancing. This was the origin of the tarantella, the dance named for a spider! In reality, a European black widow, and not the innocent tarantula, was the culprit doing the biting. The tarantula's main weapon against larger creatures is defensive. If a bobcat or fox is harassing it, the spider rises up on its front legs and with its back legs scrapes off a cloud of barbed, porcupine-like hairs from its abdomen into the face of its tormentor. This tactic sometimes gives the tarantula time to escape. It also gives rise to another common visitor query, "Why does that tarantula have a bald butt?" Although most commonly seen wandering the roads and trails in late summer and early fall, tarantulas are on the mountain all year. They are seldom seen at other times because they live in underground burrows and are nocturnal in their habits. Typically, a hunting tarantula waits patiently near the opening to its burrow until an unsuspecting insect (usually a cricket) crawls by. The spider rushes out, bites the prey, and drags its victim back into the burrow. In the dark of night, this activity goes unnoticed (except by the cricket!). This secretive existence ends in late summer, when male tarantulas that have reached about 7 years of age shed their exoskeleton for the last time. They have finished growing. The mature spiders leave their burrows and begin to search for female tarantulas. It is this horde of love struck males, searching for females with which to mate, that forms the annual "tarantula migration" park visitors witness each year in September and October. Male and female tarantulas are difficult to tell apart until the last molt, when the male spider develops little stirrups on its front legs. Why does the tarantula need these strange appendages? When the male finally locates a female tarantula and entices her out of her burrow, her thoughts are not on love but on dinner. In order to safely mate, the male spider must hook and secure the female’s fangs using the stirrups on his front legs. After mating, the male scurries away, and the female usually allows him to leave. It is a myth that female tarantulas always kill the males after mating. A female will consume the male only if she is famished and needs a meal to be able to lay eggs. Otherwise, she allows her paramour to retreat in safety. Though free to live another day, the roving male spider never returns to his burrow. Rather, he wanders around searching for other females until he finally dies with the onset of cold weather. The stay-at-home mother tarantula, by contrast, may live to the ripe old age of 20 years or more. After mating, the female retreats to her burrow and lays about 100 eggs on top a sheet of silk spun from her spinnerets. Momma spider shapes the silken sheet into a basket and guards the eggs inside until they hatch. Soon after hatching, the tiny spiderlings crawl out and leave the burrow. Of the hundred or so eggs laid, perhaps one or two spiders will survive to adulthood. It's not easy being a tarantula. In fall, pesky yellow jacket wasps are the bane of Mount Diablo picnickers. The picnickers should consider themselves lucky, for the wandering tarantula must contend with a far more formidable flying foe. The spider's antagonist is a large black and orange wasp, known as a tarantula hawk (Pepsis sp.) The female wasp flies around searching for a tarantula. When she locates one, the wasp attacks and stings the spider under a leg. This does not kill the tarantula, but it does paralyze him. The wasp drags the spider off, scraps out a hole, and pushes him in. Before she covers the tarantula, the wasp lays a single egg on the helpless spider. When the egg hatches, the wasp larva dines on fresh tarantula meat! For all their fearsome reputation, Mount Diablo’s tarantulas are really gentle souls that play an important part in the web of life on our island mountain. So the next time you encounter a tarantula on the trail, remember the old adage, "if you wish to live and thrive, let a spider run alive!" BACK TO LIST

Wildflower Mount Diablo Bermuda-buttercup, Sourgrass Invasive Scientific Name: Oxalis pes-caprae Family: Oxalidaceae Blooms: Mar - May Color: Yellow-Orange Perennial herb Introduced Non-native; bigger flower than Yellow Oxalis Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

California Red Legged Frog by Michael Marchiano April 1, 1998 Michael Marchiano The Calaveras Jumping Frog is a story written by Mark Twain in the 19th century. Contrary to popular belief, the frog in that story was NOT an American Bullfrog but rather California’s largest native, the California Red Legged Frog. The Bull frog (a non-native species) was not introduced to California until the turn of the 20th Century. The Red legged frog, is a species in decline at this time due to habitat destruction (75 % of its historical range altered), fragmentation of its environment, water pollution, pesticides, mining, fertilizers, and the introduction of the bullfrog which eats red legged frogs and tadpoles as well as its food sources. The Red legged frog can grow up to five plus inches (half the size of a bullfrog) and lives up to 8-10 years. The frogs are reddish brown, olive, or gray with black spots. The legs have a dark banding and a dark mask like steak runs from the shoulder to the front of the upper jaw. Normally found near water it will often sit on the bank blending in to its surroundings. It will use its powerful hind legs to leap into the water when threatened or attacked by a predator.It takes two to three years to reach breeding age. Breeding takes place from December to March in seasonal ponds, streams, stock pools, and reservoirs. The female can lay up to 2000 eggs but only about one percent will metamorphosis into frogs. Tadpoles mature into frogs in three to seven months, often depending on the availability of water. Water sources with shore line growth of willows or cattails are ideal breeding locations, providing hiding place. In drought years many ponds that start out with breeding populations will dry up before metamorphosis is completed. Although a riparian frog, it is capable of traveling several miles overland in rainy weather. During dry spells it often seeks refuge in leaf litter, animal burrows (especially ground squirrels and gophers) and under fallen trees. They must stay cool or wet enough so as not to dry out. Predators consist of the afore mention introduced American bullfrog, cats, garter snakes, raccoons, foxes, coyotes, egrets, bass, and introduced mosquito fish eat their eggs and newly hatched larva. Their food consists primarily of insects and other invertebrates but they have been known to eat tree frogs and small mice when available. This very attractive amphibian is now protected under both State and federal law as a threatened species. Several populations of red legged frogs breed in Mount Diablo State Park but with our current drought situation many of their breeding sites are drying up before the frogs reach maturity thus causing a decline in their population. by Michael Marchiano by Michael Marchiano BACK TO LIST

Wildflower Mount Diablo California Milkweed Scientific Name: Asclepias californica Family: Apocynaceae (Dogbane Family) Blooms: Apr - May Color: Red-Pink Perennial herb Native Toxicity: minor, dermatitis. Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

California Towhee Towhees, Sparrows, Juncos, and Longspurs California Towhee Melozone crissalis All Year Towhees, Sparrows, Juncos, and Longspurs Daniel Fitzgerald Found in brushy areas, riparian thickets, and in chaparral habitats. This brownish bird has rufous undertail coverts (compare with California Thrasher ), grayish-buff underparts, and a necklace of brown marks on throat. Bulky, cup-shaped nest is built using twigs, grasses, and plant stems. California Towhees nest in shrubs or trees. Diet is mostly seeds, fruit, or other plant matter; some insects, spiders, and mollusks are also taken.

Valley Carpenter Bee Xylocopa sonorina Apidae Xylocopa Describe your image Describe your image Describe your image Describe your image Describe your image Describe your image Description Xylocopa sonorina is a very large bee (18-26 mm in length) – a distinguishing feature in itself - with an inflated-looking abdomen (broader than the thorax). The female bee is dark-bodied with a shiny, but not metallic, abdomen (see first 2 photos, top-left). Wings of the female are dark, with a purplish and coppery tinge. Their mandibles have two teeth. Male bees are distinctly different, as they are covered in blonde/tan hair (“flying teddy-bears”) and have green eyes (see photos, top-right). Nectar/ Pollen Plants This bee is a pollen generalist, often “stealing” nectar by biting into the corolla of narrow flowers in order to gain access They also go into larger flowers. Habits These bees nest in holes in untreated dead wood such as fence posts, building structures and telephone poles. Females chew out tunnels that are 15-25 cm deep. Each cell in the tunnel receives a pollen/nectar ball and at least one egg. Larvae pupate, emerge and hibernate in their nest cells during the winter. Season March – September (Uncommon on Mount Diablo)

The Birds of Mount Diablo's Chaparral By Kevin Hintsa Chaparral refers to a type of natural habitat where the rocky soil supports a community of nearly impenetrable shrubs. Often chaparral is found on either south or west-facing slopes, locally dominated by such plants as Chamise (especially in older sections), four species of manzanita, Black Sage, Buck Brush, Jim Brush, and California Sagebrush. To the casual birder, the chaparral poses a difficult challenge to even get a glimpse of its skulking birdlife. Mount Diablo’s extensive and relatively easy accessible chaparral provides an unequaled opportunity for birdwatchers to explore its mysteries.The feathered denizens of the chaparral are notorious for being shy and can be difficult to view. Observers should take advantage of chaparral birds using conspicuous singing perches and familiarize themselves with their vocalizations. Sometimes an individual shrub (such as Toyon) can be loaded with ripe berries and will attract a large variety of birds. Many of the chaparral birds are actually very curious and can be easily attracted by a practice sometimes known as "squeaking". This is a series of assorted noises made by the birdwatcher, the principle one being a slurred call that resembles the admonishment "shhh". Note though that birds are easily frightened by sudden movements. Also, I have noticed that birds in breeding season are more easily disturbed when I wear white rather than by other colors. Extensive chaparral is located along Wall Ridge (accessible from either Rock City or Macedo Ranch) and along Knobcone Point trail (access from Curry Point). I prefer the Wall Ridge area due to recent fires. A very productive area along Summit Road is the section from the Pines Picnic Area to Pioneer Horse Camp. One of my favorite sites is Muir Picnic Area, a productive area nearly year round. White Canyon is often visited by birders, though it has rather dense chaparral and it can be difficult to view chaparral birds here. Anna's Hummingbird | Dave Furseth Spotted Towhee | Dave Furseth Breeding birds species in the chaparral include: California Quail (year round) Anna’s Hummingbird (year round) Western Scrub-Jay (year round) Bushtit (year round) Canyon Wren (year round where boulders or caves are present) Bewick’s Wren (year round) Wrentit (year round) California Thrasher (year round) Spotted Towhee (year round) California Towhee (year round) Rufous-crowned Sparrow (year round) Sage Sparrow (year round) Common Poorwill (year round, but mostly April to August, nocturnal) Ash-throated Flycatcher (April to September, needs at least a few trees) Blue-gray Gnatcatcher (mostly March to October) Orange-crowned Warbler (mostly February to September) Lazuli Bunting (April to September) Black-chinned Sparrow (mostly late April to June) In winter, look for the permanent residents plus: Sharp-shinned Hawk (commonly hunts over chaparral) Townsend’s Solitaire (rare) Hermit Thrush American Robin (mainly around Toyon bushes) Varied Thrush (uncommon) Fox Sparrow (often the most abundant species) Golden-crowned Sparrow (common) Dark-eyed Junco (a permanent resident, but more common here in the winter) Purple Finch During migration also look for: Calliope Hummingbird (rare) Rufous Hummingbird Yellow Warbler Townsend’s Warbler Hermit Warbler (mostly in May) Lawrence’s Goldfinch (nearly year round, but mostly seen in spring) California Quail | Dave Furseth Chaparral birds are not uniformly distributed, with many species showing marked preferences for certain microhabitats. Sage and Black-chinned Sparrow strongly prefer burned-over Chamise or where there are gaps in the Chamise. Rufous-crowned Sparrow usually prefers California Sagebrush or Poison Oak clumps. Old stands of pure Chamise or pure stands of Coyote Brush usually have the least interesting birdlife. Burned areas usually become very productive about 3 years after a fire. No matter what the season or the location, chaparral birding can be quite interesting with time and patience.

Wildflower Mount Diablo Clammy Clover Scientific Name: Trifolium obtusiflorum Family: Fabaceae (Legume Family) Blooms: Apr-Jul Color: Red-Pink Annual herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Steve Beatty

Geologic Guide to the Falls Trail Loop by Ken Lavin and Karen Synowiec Mountain News, Fall 1996 September 1, 1996 Falls Trail | Paul Salemme The Falls Trail loop is one of Mount Diablo's most popular hikes. In addition to impressive cascades and wildflower displays, the walk provides an introduction to the fascinating geology of Mount Diablo. The loop is six miles long, with a total elevation gain of 1,300 feet. Portions of the route are rugged, so it is advisable to wear lug soled boots. The trail head is at the end of the Regency Drive cul-de-sac in Clayton. The first portion of the trail follows Donner Canyon Road south along Donner Creek. Although Donner Canyon Road is wide and well-graded, this first part of the hike is often challenging after a heavy rain, because of the peculiar geology underlying the lower portion of Donner Canyon. These rocks belong to the 140 million year old Knoxville Formation, part of the Great Valley Sequence. These Mesozoic (Dinosaur) age rocks are composed of material weathered off the ancestral Sierra Nevada mountains and deposited into an ancient sea. The Knoxville Formation includes units of mudstone that are rich in clay minerals. Clay is extremely porous and readily incorporates water between flat, platy grains. Although porous, clay is nearly impermeable, and therein lies the problem. The "fat" clusters of water molecules cannot squeeze through tiny pore spaces between the clay grains nor overcome the electrostatic attraction exerted by the platelets. The water stays trapped in the pore spaces. The applied result of these hydrogeologic properties is a muddy goop that sticks to the bottom of your boots as you slog up the trail. About one mile up Donner Canyon, you will encounter the old Donner Cabin site on your left. Once a park residence, the cabin burned down several years ago. Beyond the cabin site, the trail climbs steeply for a short distance. As you climb, keep a sharp eye out for gray-brown chunks of sandy limestone in the soil. These chunks represent concretions encased in the Knoxville mudstone. Continue up the Donner Canyon 3/4 of a mile to the junction with the Meridian Ridge Trail. In springtime, look for the California State Flower, the Poppy, and the California State Bird, the Quail. Pause at the trail junction and examine California's State Rock, Serpentinite. Serpentinite is a metamorphic rock, created by the hydrothermal alteration by seawater of peridotite, the rock which comprises the mantle of the earth. The mantle is the layer of the earth's interior that lies between the relatively thin crust and the earth's core. Serpentinite is an ultramafic rock, rich in the elements iron and magnesium. Serpentinite also contains concentrations of nickel and chromium. This unusual mineralogy results in a distinctive plant community dominated by scrub oak, manzanita, and digger pine. Although only 1% of California is underlain by soil derived from serpentinite, fully 10% of California's endemic plant species grow in a serpentinite substrate. Turn right (west) at the junction of the Donner Canyon Road and Meridian Ridge Road, proceed uphill 1/10 of a mile on the Meridian Ridge Road and turn left at the intersection with the single-track Middle Trail. Finding the route to the falls was once a formidable task, but strategic intersections have been well marked through the determined efforts of Harvey Brossler, Paul Bennett, and other volunteers as part of an ongoing MDIA sponsored trail signage project. New trail posts have been erected throughout the park and signs are being affixed to the posts. Ranger Jay Sherman and former Ranger Burt Bogardas have also been instrumental in the project. The Middle Trail winds up the serpentinite hillside with serpentine twists and turns for 1/2 mile, to the junction with the Falls Trail. At the intersection, take the Falls Trail, which branches to the left. After another 1/4 mile climb, the trail dips to cross a creek. During the cold winter months, this creek crossing provides a truly remarkable spectacle. Here, thousands of ladybird beetles cover every rock, tree and shrub. "Ladybugs" spend the winter in semi-hibernation on Mount Diablo. When the weather warms, the ladybugs mate and fly off on prevailing easterly winds to coastal valleys where they will lay eggs to produce the next generation of beetles. As you continue up the Falls Trail, notice that the mottled serpentinite is replaced by a dark colored rock. This is basalt, an igneous rock erupted from volcanic vents on the ocean floor at tectonic plate spreading centers. These are the oldest rocks on the mountain. Radiometric and paleomagnetic studies indicate that the basalt is 190 million years old and formed thousands of miles out in the Pacific. These rocks were rafted here from their remote origin at spreading oceanic ridges by movements of the Earth's plates. The basalt is part of the Franciscan assemblage of rocks. The basalt on Mount Diablo is sometimes referred to as pillow lava. Molten rock that erupts underwater cools quickly on the outside while the inside of the flow keeps moving, pushing the mass into a tube or pillow shape. These pillow structures are especially conspicuous on the cliffs surrounding the falls. These rocks are also called greenstone because the erupting lava reacts with seawater to form new minerals, such as chlorite, which give the basalt a greenish cast. Finally, you will reach the Falls about 1/2 mile beyond "ladybug cove". Notice that the water flows over and through the basalt. Freshly formed basalt is generally not a good aquifer, but the rocks on Mount Diablo have been highly fractured over the millennia and so are able to store and transmit water to produce the seasonal waterfalls. Continue north along the Falls Trail. The fantastically contorted red rock is Franciscan chert. Chert is a biogenic sedimentary rock, composed of the recrystallized skeletons of single celled creatures called radiolarians. Radiolarians look like "amoebas in glass houses". These planktonic organisms live in the warm surface waters of tropical oceans and build their skeletons ("tests") out of silica. After radiolarians die, their tests slowly settle to the frigid bottom waters of the ocean floor to form a siliceous ooze. The ooze is buried, compressed, and over time, "lithifies" to form solid chert. Notice that the chert is in discrete layers, with bands of shale (composed of volcanic ash and fine silt blown from land) spaced in between ribbons of chert. The bedding develops when the soft ooze hardens to rock. In a process called diagenesis, the molecules of silica segregate themselves from the shale to form separate chert-shale couplets. Examine the intricate chevron folds. These folds develop during plate subduction, long after the ooze has hardened into solid rock. This is an example of "uniform flow" or "ductile deformation", in which solid rock deep underground is shaped under conditions of high confining pressure, high temperature, but low directed stress. The trail continues to climb briefly beyond the falls, then descends to meet Cardinet Oaks Road in 1/2 mile. As you descend, notice that the vegetation growing on the chert soil is rather sparse. In contrast to the Knoxville formation soil, soil derived from chert is both porous and permeable. This gives the soil a poor water holding capacity and serves as a limiting factor on the plant life. Walk down Cardinet Oaks Road and cross Donner Creek in .4 of a mile. As you cross the creek, see if you can identify the Franciscan cobbles and boulders that line the creek bed. Continue .1 miles to the junction of Donner Canyon Road, turn right, and return to the trail head. Thanks to Karen Synowiec and Roi Peers for their many helpful suggestions regarding the content and presentation of this article. Karen Synowiec is a professional geologist and MDIA hike leader. Doris Sloan, MDIA advisor, is Professor Emeritus of Environmental Studies at U.C. Berkeley. She teaches a California Geology class for the general public each spring through U.C. Extension. Along Falls Trail | Clayton Worsdell BACK TO LIST

Wildflower Mount Diablo Shooting Star (Henderson's) Scientific Name: Dodecatheon hendersonii Family: Primulaceae (Primrose Family) Blooms: February - April Color: Red-Pink Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Daniel Fitzgerald Daniel Fitzgerald Daniel Fitzgerald