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