Saturday, December 16, 2017

Say 'Merry Christmas' with California's Native Mistletoe!

Ah, mistletoe, that oft-sought-after Yuletide greenery, that oft-maligned plague of landscape trees.  What is a naturalist to do with a plant that has been so misunderstood?  As always, a lesson in ecology is in order! 

California is home to several native species of mistletoe (Phoradendron spp. and Arceuthobium spp.), which are not to be confused with the few unfortunate occurrences of the non-native European mistletoe (Viscum album) found in Sonoma county.  European mistletoe was introduced to Sonoma county around 1900, ironically by the great horticulturist, Luther Burbank.  It is not terribly host-specific, meaning it will grow happily on a wide variety of plants, but it seems to be relatively contained to one small area north of the San Francisco Bay.  The vast majority of the mistletoe across California is exactly where it is supposed to be, contrary to what most of us have heard.

With that bit of confusion is out of the way, my aim today is to dispel the myth that mistletoes - our native Californian mistletoes - are bad, and to hopefully make a convincing argument for their great value in the ecosystem.  (Aside: the same can be said for poison oak.  Marvelous plants all around!)


American mistletoe (Phoradendron leucarpum) is the species of mistletoe you're most likely to encounter in California (outside of the deserts and high Sierra, where you will encounter desert mistletoe (P. californicum) and juniper mistletoe (P. juniperinum), respectively).  One noteworthy subspecies of American mistletoe found in California is oak mistletoe (P. leucarpum tomentosum), a plant of great importance in our oak woodlands.

Clumps of mistletoe provide food and shelter for a number of species and oak mistletoe is so valuable it may be considered a keystone species in oak woodlands.  (Keystone species are defined as those that have a disproportionately strong effect on the rest of the ecosystem, relative to their abundance.)  Mammals, birds and insects rely so heavily on mistletoe that according to Kate Marianchild's book, Secrets of the Oak Woodlands (a book I highly recommend to all Californians!), removing mistletoe from an ecosystem results in the loss of one third of the ecosystem's animals.

Winter is the ideal time to scout for mistletoe, since the large, dense clumps are the only leaves left on bare, dormant trees, and beginning in December, bright white berries ripen.  Winter is when this plant really shines!


It is true that mistletoe does grow on trees.  Seeds are planted on branches by animals, and root-like structures (called haustorium) grow into the tree.  Mistletoe takes some minerals and water from host trees, but also produces some of its own food through photosynthesis, like any other respectable plant.  As such, it is considered hemiparsitic, much like paintbrushes and owl's clovers (Castilleja spp.).  And yet, none of us complain about those cheery wildflowers!

But, as you are beginning to learn, there is much to love about mistletoes as well!  The benefits these plants have on entire ecosystems are immense.

Wildlife feeds voraciously on the nectar, fruit and leaves of mistletoe (which are all toxic to humans).  When few other food sources are available, the small white-ish berries provide a source of winter food for nearly thirty species of birds, as well as squirrels and ringtails.  (A handful of those birds are: western and mountain bluebirds, phainopeplas, cedar waxwings, robins, quail, flickers, scrub jays, thrushes, thrashers, warblers, juncos and goldfinches.)

Bullock's orioles and phainopeplas sip nectar from inconspicuous mistletoe flowers, alongside great purple hairstreak butterflies which lay their eggs exclusively on the leaves of our native mistletoes. 

Squirrels, mice, chipmunks and porcupines eat nutritious mistletoe leaves directly from the plants high in the canopy, while deer, elk and pronghorn browse beneath mistletoe-bearing trees for fallen leaves.

Dense clumps of mistletoe provide shelter for birds and mammals, and some species, like white-tailed kites, black-throated gray warblers, wrens, chickadees and bushtits, build their nests in them.  Spotted owls also nest in these "witches' brooms," as the thick, tangled masses of mistletoe branches and leaves are sometimes called.  I have read that nifty, seldom-seen critters like porcupines, martens and flying squirrels can be found curled up in mistletoe balls during the winter, seeking shelter from the cold.

An American Robin sits on its nest constructed in a "witches' broom," or clump of mistletoe, one rainy spring day along
the Stanislaus river (San Joaquin county)

Research indicates that mistletoe is not as harmful to healthy trees as once believed.  The growth rate of mistletoe is quite slow, so it steals negligible amounts of water and minerals from host trees.  However, during extended drought (a familiar thing in California) trees may become stressed if they are losing water to multiple clumps of mistletoe.  This may result in the death of trees that are genetically weaker and less tolerant of dry conditions, improving the gene pool over time - a benefit in disguise.  I'm also surmising that our imported ornamental trees, so often planted in city landscapes and victims of mistletoe infestations, don't get along well with our native mistletoes, not having "grown up together," so to speak. 

Additionally, let us remember that standing dead trees and snags, cavities left behind where dead limbs have broken off, and fallen logs on the ground are all essential parts of the ecosystem, providing valuable habitat for cavity nesting birds (swallows, bluebirds, screech owls and the like) as well as mammals, reptiles and amphibians.  One National Wildlife Federation source I read stated that a forest with mistletoe, and therefore branches and trees killed by mistletoe, supports three times as many cavity-nesting birds than a forest devoid of mistletoe. 

If you find yourself beneath a sprig of mistletoe this Christmas, may it remind you of the amazing, awe-inspiring ecosystems that are all around us.

Thursday, December 7, 2017

Mountain Bluebirds

Mountain Bluebirds (Sialia currucoides) are one of the West's dazzling surprises; no bright Painted Buntings or Northern Cardinals* for us Californians, but we do have our own little collection of brilliantly-colored birds, which happily includes two bluebird species (Western Bluebirds (Sialia Mexicana) being the second).  Female Mountain Bluebirds, pictured below, are doe-eyed beauties in their own right, modestly showing only hints of bright blue along their wings and tails. 

Female Mountain Bluebird at Tuolumne Meadows

Male Mountain Bluebirds are the real lookers: they are as vividly blue as the clear sunny heavens above the alpine firmament they call home.  To see one of these gems flutter from above to perch on a branch, you may even believe a little piece of the sky has just fallen before you.  They are absolutely breathtaking.

The unfortunate and less poetic truth of the matter is that as of yet, no male Mountain Bluebird has seen fit to pose for a portrait for me!  Mountain Bluebirds spend most of the year in open areas from mid to high elevations in the Sierra and across western North America.  (Try looking for them at Yosemite's Tuolumne Meadows.)  In the winter, they venture to lower elevations and may make appearances in the Sierra Nevada foothills and the Great Central Valley's grasslands and farmlands.

In contrast to Mountain Bluebirds, Western Bluebirds (pictured below, for the sake of comparison) are stockier and a much deeper, richer blue color; males and females both have a rusty red/orange wash on their breast, flanks and back.  (I should also mention that in the Central Valley, year-round, you are far more likely to see Western Bluebirds than Mountain Bluebirds.) 

Western Bluebird along the Tuolumne River in Stanislaus County

Bluebirds of all kinds (including North America's third species, the well-known Eastern Bluebird (Sialia sialis)) are in the thrush family (Turdidae) along with robins, solitaires and, well, thrushes.  They are cavity nesters, and Mountain Bluebirds have historically nested in holes excavated by woodpeckers; they readily take to human-made nest boxes as well, which has allowed researchers to study them fairly easily.  As with other native birds that nest in cavities (like Tree Swallows), competition is fierce from non-native, introduced European Starlings and House Sparrows.

*Note: Upon further investigation, it looks like a few Northern Cardinals do turn up in southern California now and then, probably naturalized individuals from introduced stock.  As a general rule, they are considered rare here.

Friday, December 1, 2017

American Goldfinch

As the leaves fall from the trees to reveal bare branches and migratory birds arrive, birding really begins to get interesting in December!  One striking bird you may encounter this winter in backyards and wild lands across the Great Central Valley is the American Goldfinch (Spinus tristis). 

Male American Goldfinch, showing some typical patchiness (the gray feathers) due to seasonal molt. 
These finches molt twice a year - once in late winter and again in late summer.

Winter goldfinches are not as brightly colored as they are in the spring and summer and their coloring can be highly variable.  But they are still recognizable by their conical bills and wingbars.  Goldfinches readily visit bird feeders, especially during the winter, and are particularly fond of sunflower and nyjer (thistle) seeds.  In wilderness areas, look for goldfinches in open, weedy fields with thistles, sunflowers and asters - favorite food sources.  They also feed on the seeds of grasses and some trees, like alder, birch and elm.


Interestingly, American Goldfinches are one of the few birds that eat an almost strictly vegetarian diet of seeds - no insects.  When parasitic Brown-headed Cowbirds lay their eggs in American Goldfinch nests, the cowbird young can't survive on this seed-only diet and soon die.  American Goldfinches nest late in the summer (July-August), which likely ensures a plentiful crop of seeds to feed their young.


American Goldfinches (as well as closely-related Lesser Goldfinches (Spinus psaltria)) are common backyard birds, gathering in numbers at feeders and on the ground beneath them.  To attract them to your yard, plant native seed-bearing plants.

In California, try our native western redbud, coyote brush, California rose, buckwheat, salvia, milkweed, goldenrod and asters.  Other garden favorites that goldfinches enjoy include sunflowers, cosmos, purple coneflowers and zinnias.  Just resist the urge to deadhead your garden flowers at the end of the season, as the mature seeds in the dried seed heads are what the birds are after!  Additionally, you can supplement with bird feeders (any style) and fill them with sunflower and nyjer (thistle) seeds.  Since they also will feed on the ground beneath feeders, it's important to keep the ground raked to prevent the spread of disease.

Tuesday, November 28, 2017

Sea Monkeys!! (Brine Shrimp of Mono Lake)

Mono Lake, an otherworldly spot east of the Sierra Nevada in California's Great Basin desert, is such a fascinating place in so many ways, I could spend days reading and writing about it.  The geological history of the area is rich: Mono Lake, a salty inland sea with no outlet, sits in a fault basin and was formed from the melting of glaciers during the last ice age.  The glacial history written in the bordering mountains and the volcanic history seen in nearby craters, Mammoth Mountain, the Long Valley Caldera, and islands in Mono Lake itself are all worthy topics of study in their own right.  And the lake's famed tufa towers certainly deserve the spotlight in an article of their own, as do my beloved plants - in this case, those plants that have evolved to tolerate not only harsh desert conditions, but extreme salinity and alkaline soils as well!  The wonders are new every morning at Mono Lake! 

Shoreline at Mono Lake's South Tufa Area
 
Political struggles surrounding the lake have been quite fierce.  The lake is fed by streams flowing from the Sierra Nevada, but water was diverted from these streams and sent to water the landscapes and booming population of Los Angeles beginning in 1941.  As a result, lake levels dropped 45 vertical feet.  (That is a story for another day; suffice to say that for now, at least, while the future of the lake is not entirely secure, conditions are an improvement on what they have been.)
 
But today, I'm more interested in discussing the ecology of Mono Lake, focusing on one of its most famous inhabitants: the sea monkey.
 
Little greenish brine shrimp, each about 0.4 inches long.

Brine Shrimp (yes, they really are the very same critters sold in shops under the name "Sea Monkeys") form an integral part of Mono Lake's food web.  The lake boasts its own unique species of brine shrimp, Mono Lake Brine Shrimp (Artemia monica), an enchanting, translucent-greenish little crustacean.  The salty, alkaline lake waters absolutely teem with billions of these little guys; estimates put their numbers around 5 trillion during the summer months.  And insignificant though they may seem, the ecosystem would collapse without them.
 
The lake initially appears "dead" and desolate to any casual observer, and it's true that the ecosystem found here really is comparatively simple, with just a few key species.  But the lake is far from a "dead sea" and the species that do survive here are present in massive numbers, which makes all the difference. 
 
Brine shrimp in a shallow disc (ok, it's a Frisbee).  They're barely visible in the photo above, but you can see one where
the finger is pointing.  This gives a sense of just how tiny brine shrimp are.

The ecosystem of Mono Lake is a great teaching tool for illustrating the concept of a simple food web.  The entire ecosystem is based on three key species: algae, alkali flies, and brine shrimp.  Green algae is photosynthetic, using the sun's energy to grow and obtaining nutrients from the lake water.  Alkali flies and brine shrimp feed on the algae.  Over a million birds flock to Mono Lake every summer to feed on the flies and shrimp, including gulls, phalaropes, grebes and others.  Waste from the birds and dead organisms sink to the bottom of the lake to decompose and act like fertilizer for the algae.  And so, the cycle is complete! 
 
Notice that there are no fish in Mono Lake.  With a pH of 10 (on a scale where 7 is neutral), the lake's waters are far too alkaline to support other life.  The water is also 2.5 times saltier than the ocean!
 
Alkali flies around a puddle on the lake shore.  They may not look appealing, but they are a critical part of this ecosystem.
Also, we noticed the flies don't bother people, so don't worry about them and leave them be.
 
Hardy as they are, brine shrimp cannot overwinter in the cold lake as adults.  Late in the season, before they die, the shrimp produce eggs designed to overwinter as "cysts."  These tough cysts sink to the bottom of the lake where they persist in a state of suspended animation until the water warms sufficiently the following spring.  These hard, leathery cysts or eggs are what is harvested and sold as "Sea Monkeys" and fish food.
 
The huge abundance of aquatic life found in Mono Lake during the summer makes the lake one of the most important sites for nesting and migrating birds in the west, particularly as other western wetland habitat has been lost to development. 
 
Two gulls, happily foraging in Mono Lake.
 
Though the ecosystem of Mono Lake thrives in a combination of harsh conditions, including desert heat, winter cold and extremely high salinity and alkalinity, it is remarkably fragile.  Because it relies so heavily on just a few species, the loss of even one species, such as the brine shrimp or the alkali fly, would be catastrophic for dependent populations - especially birds.
 
 
Abundant numbers of these tiny creatures does not necessarily guarantee a stable ecosystem, safe from collapse.  Since the entire ecosystem is essentially built on just three groups of organisms (algae, brine shrimp and alkali flies), it is very susceptible to climate change and other damaging factors.  Since brine shrimp and alkali flies are ancient, primitive creatures perfectly adapted to the saline, alkaline waters of Mono Lake, a rapid change in the lake's chemistry would likely prove too much for them to handle and result in population collapse. 

Diversion of streams from Mono Lake began in the 1940's and was finally stopped 40 years later.  Between that time, the salinity of the lake doubled (as half of the lake's volume of water was lost) and the productivity of the brine shrimp and alkali flies dropped significantly.  The loss of either one of these species would mean disaster.  In particular, the failure of the brine shrimp population one year would mean starvation for thousands of birds.
 
As you may know by now, flipping over rocks often reveals a treasure trove of unseen life.  Underneath this piece of tufa
is the remnants of dozens of alkali fly pupae.  Birds are happy to eat alkali flies during all life stages, but the pupae were
once an especially important food source for local native people.
 
If you visit:  I highly recommend stopping to check out the Mono Basin Scenic Area visitor center on highway 395 and going on a docent-led walk at the South Tufa Area along the lake.  Other activities include hiking, birding, kayaking and swimming.  (We went swimming at Navy Beach and loved it!  The water is dense, making it easy to float, but all that salt makes it important to remember to keep your mouth closed!  Also, the salt forms a crust on your skin and brine shrimp may get stuck in your hair!  Still, it's a worthwhile experience.)
 
For more information, visit: http://www.monolake.org/visit/activities

Tuesday, November 21, 2017

Notable Monotropes: Snow Plants & Pinedrops

A week or two ago, while hiking in the Wawona area of Yosemite National Park (taking in the glorious fall colors and hoping beyond hope to see a Great Gray Owl), I came across a dried up stalk of Woodland Pinedrops (Pterospora andromedea) growing on the forest floor.  I'm sure most people would have walked right on by, but of course I was thrilled!  I stopped to take a bunch of photos (Eric wondered, I'm sure, what all the fuss was about over something so seemingly unspectacular) and once home, decided it was time to introduce you to a few of California's magnificent monotropes!

Dried stalk of Pinedrops - unassumingly beautiful!

Pinedrops are a lesser-known cousin of the showy Snow Plant (Sarcodes sanguinea), both of which are included in the heath family, Ericaceae.  Other plants in this family include California's 40+ manzanita species, John Muir's beloved Cassiope, the abundant Salal of the Pacific Northwest, and common favorites like rhododendrons, blueberries and huckleberries (plants with urn-shaped flowers).  But Snow Plants and Pinedrops are also considered members of the Indian-pipe subfamily, Monotropaceae, a group of mycoheterotrophs or mycoparasites, plants that obtain nutrients by parasitizing fungi.

Snow Plants have long been misclassified as saprophytes.

(And here we must stop to define saprophytes!  A saprophyte is an organism - a plant, fungus or microorganism - that lives on dead and decaying organic matter.  Ecologically, they are heterotrophs (consumers, like animals) rather than autotrophs (producers, like other plants) within the food web.  Fungi like the familiar and humble mushroom are common examples of saprophytic organisms.) 

Since Snow Plants and their kin lack chlorophyll and are therefore incapable of manufacturing their own sugars, they were once thought to belong to this group of saprophytes, living on dead organic matter.  But that turns out not to be entirely correct.

Snow Plant growing in forest humus at the foot of a pine

Snow Plants and Pinedrops, as well as other monotropes, may also be considered parasitic on the roots of the pine trees they are so commonly associated with, but that isn't quite the whole story either. 

To really get down to specifics, we must first understand the symbiotic relationship that exists between conifers and underground mycorrhizal fungi.  Then we can begin to understand that Snow Plants are actually parasites on this fungi, rather than on tree roots, obtaining nutrients from the mycorrhizae.  They are, in fact, mycoparasitic, a term meaning parasitic on fungi.

Mycorrhizae (a word which literally translates to "fungus-roots") are an essential part of the forest ecosystem, and many conifers (as well as other plants) depend on these fungi to live healthy lives.  Strands of cells called mycelia make up the mycorrhizae, growing in a web throughout the soil and root systems of forest plants.  Mycelia effectively become extensions of plants' root systems, enabling them to take in water and nutrients more efficiently.  The relationship is mutually beneficial, as the trees provide the fungi with energy (the products of the trees' photosynthesis, known as photosynthate) and the fungi provide the trees with a more efficient system of nutrient uptake. 

Snow Plants essentially steal some of this energy, or photosynthate, from the mycorrhizae, which had obtained it fairly from the trees by means of the aforementioned agreed upon exchange of goods and services.  Monotropes are then, essentially, fascinating little freeloaders.

Summer flowers of the Snow Plant

Though it may not look like it at first glance, the Snow Plant in bloom really is covered in little downward-pointing flowers and produces seeds when pollinated, just like other angiosperms.  It is considered an "herbaceous perennial wildflower," though alien-like fungi-creature might initially seem more appropriate!

The Snow Plant is not common, and belongs almost exclusively to California; some are found in Nevada and Oregon as well.  It grows up to 20 inches tall, and is found singly or in clusters on the floor of coniferous forests.  They thrive in the thick humus of the montane region from 4,000 to 8,000 feet in elevation.  Typically Snow Plants are in bloom from April or May to July, sometimes poking brave scarlet heads up through melting snow.  When you meet the Snow Plant, you are unlikely to mistake it for anything else!

November seed capsules of Pinedrops

Woodland Pinedrops are also covered in tiny flowers when in bloom, which generally happens during the late summer, though they seem to be particular little plants and cannot be depended on to come up every year.  Pinedrops are fairly uncommon, though their range covers much more of the United States than the Snow Plant.  Habitat preferences are similar to that of the Snow Plant and other monotropes, found growing on dark forest floors in association with conifers such as Ponderosa Pine and Douglas Fir.

California is home to a few other notable monotropes as well: Pinesap (Monotropa hypopitys) and Indian Pipe (Monotropa uniflora), both of Northern California; Sugar Stick (Allotropa virgata), Fringed Pinesap (Pleuricospora fimbriolata) and rare California Pinefoot (Pityopus californicus) of montane forests; and the redwood forests' own Gnome Plant (Hemitomes congestum). 

So, while birds and boughs beckon your gaze upward, next time you are strolling through the evergreens pay some attention to the dark forest floor as well and see what interesting plants may await your discovery there!
 

Friday, November 17, 2017

Northern Pintail

With delicate chocolate-brown heads and characteristically pointed tails, the Northern Pintail (Anas acuta) is the duck species I consider to be the most elegant.  Northern Pintails assemble in freshwater wetlands across the Great Central Valley during the winter months, and are usually one of the first species to arrive in great numbers, perhaps second only to Northern Shovelers.  Northern Pintails are quite common birds across North America, Europe and Asia and there's a good chance that you will encounter them on any trip to a Central Valley wetland or wildlife refuge between October and March.  (Though they do reside in the valley year-round and a few even breed here - I'm not sure where! - their numbers are highest in the winter when augmented by migrants from the far north.)


The summer breeding range of the Northern Pintail covers much of Canada (especially in the west) and Alaska, as well as northerly states such as Montana and the Dakotas.  Their preferred habitat is open, with low vegetation and wetlands, including tundra, prairie and farmland.  Nests of the Northern Pintail consist of shallow scrapes on the ground, concealed by grasses or brush and lined with downy feathers; typically they nest a considerable distance from the water (as much as half a mile).


Pintails are dabbling ducks (as opposed to diving ducks), filter feeding at the surface and turning tail-end-up in shallow water in search of food.  Plant matter such as weeds and seeds, as well as aquatic insects, mollusks and crustaceans make up the bulk of their diet. 


Since the 1960's, numbers of Northern Pintails have declined by 72% across their range, earning them the distinction of "Common Bird in Steep Decline."  Threats may include drought in their northern breeding range and, as always, habitat loss.


Read more here: https://www.allaboutbirds.org/guide/Northern_Pintail/id 
and here: http://www.audubon.org/field-guide/bird/northern-pintail

Thursday, November 16, 2017

Painted Lady Butterfly

The Painted Lady (Vanessa cardui) is quite the cosmopolitan butterfly.  Found on every continent except Australia and Antarctica, it is considered by some to be the world's most widely distributed butterfly.  Additionally, it is one of the most common and familiar butterflies across all of North America.  Certainly the Painted Lady is a species that merits getting to know! 


These pretty orange-and-black Lepidopterans are found in a variety of habitats, though they are perhaps most frequently encountered in open or disturbed areas, such as gardens and fields.  Females lay eggs on over a hundred different host plants, with thistles and mallows seemingly among their favorite.  Adults favor nectar from thistles and other members of the aster family, and will also partake of more standard butterfly fare, such as clover and milkweed.  Most of our Painted Ladies in California overwinter in the desert parts of the state near the southern border, and begin their northward migration in the spring.

Thursday, November 9, 2017

Plant Profile: Jimsonweed (Datura wrightii)

When it comes to choosing topics to write on, I generally let the seasons dictate.  A walk outside reveals a host of ideas, and most often I like to write in keeping with current happenings in the natural cycle of seasons.  Hence, the autumn months ought to be filled with information on migrating Monarchs, colorful leaves and the fall salmon run.  But at other times, an older photo jogs a memory or a book sparks an idea and I'll find myself reminiscing about the springtime desert in the fall, or summer in the Sierra during the depths of winter.  At still other times, a topic might not be as far-fetched as it may seem.


Wildflowers, you might think, fall exclusively into the territory of spring and summer but that's not quite so, as California's mild Mediterranean climate tends to defy expectation.  With the start of what is supposed to be California's rainy season, autumn rather than spring marks the beginning of our growing season.  Hillsides that have lain golden and dormant during the long, dry summer (the real "winter" for plants here) begin to sprout with new growth: summer-dormant shrubs awaken and wildflower seeds in the dry earth begin to stir.  The seasons in California are effectively reversed, with a long, hot dormant period during the summer, and the "spring" growing season beginning in autumn.  Here in our Mediterranean climate, wildflowers come and go as they please, with something pleasant blooming at all months of the year.


And so it is that we find the dazzling white trumpet flowers of Jimsonweed (Datura wrightii) carpeting wasteland areas across the state, blooming continuously from early spring through late fall.  This oft-maligned plant is generally relegated to the realm of "weeds," but is in fact a native of California and the southwest.  It has a way of making the most of things, as all weeds do, and thriving in the most unlikely of places.  Look for Jimsonweed blooming along roadsides and other neglected places throughout much of the state (except maybe in the Sierra and northern mountains). Jimsonweed is at home on a variety of soil types from sand to clay and gets by on little water.


In honor of its exquisitely beautiful flowers, D. wrightii is also known by the names Angel's Trumpet and Moon Lily.  Jimsonweed is in the nightshade family (Solanaceae) along with our familiar garden tomatoes and potatoes.  But be aware that all parts of the Jimsonweed plant are potentially lethal if ingested, as suggested by still other common names: Devil's Trumpet, Deadly Nightshade and Locoweed.  During religious ceremonies, native people of the southwest used the plant for its narcotic properties, earning it the moniker Sacred Datura.  The moral of the story: admire the flowers, but don't get too friendly; perhaps it is best to leave the flowers for the pollinators! 


At night, Datura flowers are visited by Hawk Moths and Sphinx Moths of the family Sphingidae.  The larvae of these moths, known to gardeners as tomato hornworms, might be familiar to you.  It's best to leave these critters alone though, as the agricultural application of pesticides has reduced the numbers of hawk and sphinx months, meaning there are fewer pollinators out there to pollinate neat desert plants like the Queen of the Night cactus and our new friend, Sacred Datura.

If you're interested, a more detailed article on Sacred Datura can be found here:
https://www.desertusa.com/flowers/datura-jimson-weed.html

Sunday, November 5, 2017

Plant Profile: Apricot Globe Mallow (Sphaeralcea ambigua)

Oh, the Apricot Globe Mallow!  Be still my heart!  This humble mallow is perhaps my favorite desert shrub, bursting forth as it does in glorious coraly-salmon bloom.  (Some sources call the blooms "orange," but once you spend some time with this plant you will see that bland description doesn't quite do the color justice.)

 
Apricot Globe Mallow (also called Desert Globe-mallow, Desert Mallow, Apricot Mallow, Globe Mallow or seemingly any other combination of those words) is a member of the mallow family (Malvaceae) along with the familiar garden hollyhock.  The plant is a shrubby perennial that grows from about 1 to 3 feet tall and wide, depending on its location.  The leaves are gray, fuzzy and roundish with scalloped edges, much like those of a hollyhock.
 
Apricot Globe Mallow with Joshua Trees, Joshua Tree National Park

This globe mallow is found across the desert southwest on dry, rocky slopes as well as sandy washes.  Its range extends across the Mojave and Colorado (Sonoran) deserts of California, into Nevada, Utah, Arizona and Mexico.  Last year, we found a spectacular showing of Apricot Globe Mallow in Joshua Tree National Park as well as Mojave National Preserve and the higher elevations around Death Valley. 


The Apricot Globe Mallow is reputed to be the most drought-tolerant of all the mallows.  The plants provide a source of browse for Bighorn Sheep (Ovis Canadensis) and the flowers are an excellent source of nectar for native bees and other pollinators, such as butterflies and hummingbirds.

Along a desert wash, Joshua Tree National Park

Apricot Globe Mallow is typically associated with creosote bush scrub and desert chaparral plant communities, though it can also be found in pinyon-juniper woodlands, below about 4,000 feet in elevation.


These plants are also great candidates for a garden of California native plants in the hottest and driest parts of the state (and I would include the San Joaquin Valley in that category!)  The photo below was taken in the native plant garden at Kern National Wildlife Refuge in early April.  Absolutely stunning!

Wednesday, November 1, 2017

Tiny, Twittering Bushtits

At only three inches long, tiny Bushtits (Psaltriparus minimus) might go unnoticed by most, flitting through the foliage in loose flocks.  But once you've learned their diminutive calls you'll begin to notice the lively twittering of these little songbirds in suburban backyards as well as wilderness areas of the Great Central Valley.  They move almost constantly as they forage for small insects in shrubs and trees across the western United States, and are often found in flocks associating with other small, sprightly songbirds, such as kinglets, warblers and chickadees. 
 
 
Female bushtits can be distinguished from males by their pale eyes (pictured above and below); male bushtits have entirely dark eyes.  Together, the male and female of a breeding pair build a hanging nest that looks sort of like a dirty gym sock hanging in a tree (at first glance, of course).  The nest is about a foot in length, and the building process can take over a month to complete. 
 
The sack-like nest is built using stretchy spider webs and plant material.  The birds use their weight (all 5 grams of it!) to create the elongated shape by sitting in the nest letting gravity pull it downward. The inside of the nest is lined with soft material, like downy plant material, fur and feathers, while the outside is cleverly disguised with bits of lichen and other nearby plant matter.  
 
A female Bushtit outside her nest in a Valley Oak.  Notice the round entrance hole near the top of the nest.

Interestingly, other adult bushtits help the breeding pair raise its young; more interestingly, these adult "helpers" are generally males.  During the breeding season while the nest is in use, all members of this family-like group will sleep together in the nest.  Once the young have fledged (left the nest), the birds roost in trees at night.  Groups of bushtits may huddle together for warmth during cold weather.  Bushtit flocks change their ranges throughout the year in a constant hunt for food, but they don't truly migrate.


Bushtits are not showy birds by any means, but they are abundant.  Listen for the soft, continuous chipping or "lisping" communication calls of bushtit flocks, and expect to see these cute little birds throughout much of California all winter. 

Thursday, October 26, 2017

Life Along a Valley River: The Tuolumne

In days gone by, California's Great Central Valley was crisscrossed by a handful of free-flowing rivers carrying snowmelt from the Sierra Nevada to water fertile grasslands below.  Natural flood plains were regularly inundated with nutrient-rich silt, and wetlands of tule reeds and myriad wildlife flourished.  Today, the rivers persist in a somewhat diminished state, rigidly controlled by upstream reservoirs and dams.  Fruit and nut orchards, vineyards and housing developments have spread across the valley, to the very edges of river bluffs. 

The view west, down the Tuolumne River in Stanislaus County.

Earlier this year, flooding was a major concern in many areas along the rivers, the water flowing fast and strong.  But last year, like many years, the Tuolumne River was low and fairly calm, allowing for natural explorations of the riverine ecosystem.  Now, in the fall, the river has returned to its placid state.  When the river is quiet, pleasant hours can be spent wandering its banks and peering into the shallows.  Where the Tuolumne leaves the foothills and begins its journey across the valley to join the San Joaquin River, there are a few spots that have become special to me.

Damselfly resting along the edge of the Tuolumne River, a natural and beautiful part of this ecosystem.
 
Unfortunately the rivers of the Great Central Valley, which once offered life-giving abundance to wildlife as well as humans, have been greatly diminished and disrespected over the last century.  The rivers were manipulated, their natural cycles of flooding disregarded, their native vegetation uprooted and indigenous species supplanted by aggressive exotics. 
 
Bullfrog tadpoles lurk in quiet waters.  This introduced, invasive frog gets to be quite large as an adult and preys on
anything that will fit into its mouth, including native species of fish and frogs, even ducklings and turtle hatchlings. 
Bullfrogs are destructive to the native fauna and efforts have been made across the state to eradicate them.
 
I like to think that today, we have reached a turning point in our relationship with the rivers.  I like to think that we have learned our lessons and hence forth will do a better job of protecting our rivers and watersheds.  Many individuals and organizations do just that, and the results are encouraging.  But the sad truth is, our rivers are still corridors for invasive species, and their banks and beds still collect trash and bare the scars of careless humans.  Why are our rivers so subjected to becoming trashed and polluted, these beautiful riparian ecosystems damaged beyond recognition? 
 
Purple Loosestrife: though beautiful, this introduced ornamental plant has escaped
gardens and now out-competes native vegetation along our rivers.
 
Where once grew Valley Oaks, there now grow almonds.  Riparian areas were once thriving ecosystems, multi-storied forests akin to tropical rainforests in their complexity.  Canopies of oaks and cottonwoods gave way to understories of willows and elderberries.  Thickets of native blackberry brambles and wild rose bushes formed a dense carpet beneath, and the whole assemblage was intertwined with vines of wild grape and filled with wildlife.  Today, these forests are very different, if not gone entirely. 

We can still find protected remnants of what used to be, though the glorious riparian forests have been largely replaced by a scattering of weedy non-native species: Tree of Heaven (Ailanthus altissima) and escaped ornamentals line the riverside bluffs, purple loosestrife and exotic annual grasses carpet the banks and water hyacinth chokes out life in the quiet waters.  Old tires, beer bottles, abandoned ice chests, rusty cans, broken flip flops, carelessly discarded fishing hooks and more yards of wildlife-threatening fishing line than I care to think about now fill our rivers and adorn their banks. 
 
Evidence that even in their diminished state, valley rivers do indeed support life!  This felled tree is evidence of beaver
activity.
 
I can only conclude that we have almost entirely lost touch with the river ecosystems that our predecessors, the former inhabitants of our valley, once knew so intimately.
 
Therefore a remedy to the current sad state of our rivers, or at least the beginning of their restoration, must come from a reintroduction to the wonders that are found in the life along a valley river.


Find a quiet spot to venture down to the river.*  Wade in the shallow water along the edge and watch tiny fish and tadpoles scurry out of your way.  Flip over a rock to examine the life beneath.  Follow raccoon tracks along the bank and watch quietly for otters and beavers.  (Beavers, while sometimes accused of being pests, are really great hydro-engineers, vital to a healthy ecosystem.)  Notice an osprey or hawk soaring above, a belted kingfisher calling loudly from its perch, acorn woodpeckers busily working in the oaks.  Black phoebes chirp from conspicuous branches, and during the summer months, swallows dart across the surface of the water catching insects on the wing.  If you're lucky, you might catch a glimpse of a Western Pond Turtle (California's only native turtle) basking on a log.  I've seen evidence of beavers, river otters, raccoons, foxes, opossums and even shrews along our rivers, and over 50 species of birds along just one small section of the Tuolumne River. 

Flip over a rock... and you might find flatworms!  Though not much to look at, these little guys are just one small part of
a much larger and immensely complex ecosystem.

To peer into a miniature world, take a closer look at the insect and other invertebrate life that abounds in and near rivers.  Dragonflies and damselflies are easily seen and recognized, but less familiar to many are their aquatic larvae.  Crayfish, though introduced in the valley, are fun to watch as well as catch.  Peek underwater for a look at the world beneath the surface, where bass and bluegill (introduced for sport fishing) swim along the rocky bottom.  In the fall, it's a fascinating thing to watch the annual salmon migration and spawning.


Beneath the surface, it's mesmerizing to watch bass, bluegill and other fish glide quietly through the water.  (Whoever said snorkeling is just for Hawaii?)

 
Perhaps slowly we will become reacquainted with rivers and the life found there.  First we may notice the singing birds, a jumping fish, an otter sliding quietly beneath the surface, and we will remember that the rivers belong not only to us.  Then maybe we will be moved to pick up a piece of trash, pull a few invasive weeds and clean up a jumbled tangle of fishing line.  Perhaps, one inspiring discovery after another, we will regain our collective appreciation for our precious rivers.
 
* Explore safely, and remember to be aware of your surroundings!  Rivers are always unpredictable. 

Wednesday, October 25, 2017

Mountain Garter Snake

I am not exactly the biggest snake fanatic you'll ever come across, but I have learned to appreciate the role these legless reptiles play in the wide variety of ecosystems they inhabit.  Several times this year I've crossed paths with Mountain Garter Snakes (Thamnophis elegans elegans) while hiking in the Sierra Nevada, and one snake in Tuolumne Meadows was kind enough to pose for a few photos.
 

The Mountain Garter Snake is a subspecies of the Western Terrestrial Garter Snake, found in the Sierra Nevada mountains.  These snakes have a prominent yellow dorsal stripe, along with a lighter stripe on each side of the body.  They range in length from 18 inches to 43 inches (three and a half feet!) and prefer to inhabit damp areas, retreating beneath vegetation or rocks and logs when threatened.  Other subspecies and species of garter snakes tend to be more aquatic and regularly take to the water.  Garter snakes give birth to live young, as opposed to laying eggs like many other snake species. 


Mountain Garter Snakes are generalists when it comes to feeding and will take a variety of prey.  They have been found to eat worms, slugs, frogs, small fish, lizards, other snakes, small rodents and insectivores, birds and birds' eggs, and a number of other prey items when available.  But fear not: as members of the Colubrid family, garter snakes are non-venomous and generally harmless to people and pets.  (Happily, two thirds of California's snake species belong to this group!)

Friday, October 13, 2017

Milbert's Tortoiseshell

Milbert's Tortoiseshell (Aglais milberti), a striking and unmistakable Lepidopteran, is typically a butterfly of mountain meadows.  I found this individual "puddling" in a meadow near Lake Tahoe, along with a Hoary Comma.  Commas and Tortoiseshells are closely related members of the Brush-foot family (Nymphalidae).


Many butterflies are attracted to damp soil and engage in a common behavior known as "puddling."  While we typically picture butterflies delicately sipping nectar from flowers, many species obtain their nutrients from a surprising variety of sources, including rotting fruit, sap, dung, carrion and mud.  It is believed that butterflies, especially males, obtain salts and minerals from mud.

The brown underside of the wings provides camouflage as these butterflies hibernate during the winter. 
Also note the butterfly's extended proboscis (feeding organ) taking in nutrients from the mud.