Grass Spiders

I walk out of my office on a chilly December day. I pull my coat up around my neck to block the wind, and make my way out to the grassy hill with a view. The hill, where I took pictures of wildflowers in lush green in April, and watched buckeye butterflies in the crispy dry grass in August, is just starting to turn green again. It's dotted with patches of glittering white. The white patches are spider webs, covered in dew.

Bending close I see that each one has a funnel, or two or three. The funnels curve toward the ground. I can't see how far down they go.

A little research reveals that these webs are made by grass spiders. There are several local species, all in the genus Agelenopsis. Grass spiders are slender, brown and beige spiders. Their webs are not sticky, but the spiders move very quickly and rush out from the funnel to catch prey when vibrations on the webs cue the spiders to emerge. They are mostly nocturnal, end even then, spend most of their time tucked in their funnels, so they are rarely seen.

The grass spiders' webs are there on the hillside all year long, but I didn't notice them until now. The cool temperatures and moist air of December bring the dew, which outline the webs in glittering beads of water. It's an interesting twist on seasonal nature: the organism isn't doing anything differently this time of year, but changes to the environment highlight its intricate works.

LINKS:

Information on grass spiders from bugguide.net

Guide to common Bay Area spiders

Mysterious Creatures in the Wood Chips

I had seen the bizarre photos on the internet, the mysterious pods, the fleshy geodesic domes. I set off to find the creatures for myself. I checked the location tags on maps, traced pathways on campus, prodded under ivy, scanned wood chips. Failure after failure. I began to wonder if it wasn't all a hoax, a goose chase. Then one day, just outside the library, with undergrads walking by as though everything were normal, I spotted one. A latticework ball the color of boxed macaroni and cheese hunkered amid the mulch, its gooey red interior peeking out between the struts. Next to it, another was just emerging from its cracked white egg.

I bent close to examine the creatures and a noxious wave of filthsome stench assaulted my nose, staggering me backward.

This is the basket stinkhorn, also known as latticed stinkhorn or red cage fungus. It lives in decaying plant matter, especially wood chips, and each fall it sprouts these astonishing fruiting bodies. The basket stinkhorn is originally from the Mediterranean but is now found on every continent except Antarctica. The odor attracts flies and beetles which eat the gooey center and spread the spores that form there. 

The basket stinkhorn is not the only mysterious visitor making its home in our landscaping mulch. A week or so later, again after several rounds of searching, I came upon another. Deep under a spiny thistle, a cluster of mushrooms raised smooth russet caps on bright white stipes. Delicate webbing laced the underside of the cap. I picked one and pressed the stipe with my thumbnail. The white slowly blushed blue. 

Several more of these psilocybe allenii mushrooms sprouted in this weedy patch. There must have been some irrigation leak because the woodchips here were damp though it hadn't rained for months. This species was discovered in 2012, when genetic analysis differentiated it from other psilocybe species. It's found all along the west coast of the United States and has almost certainly spread to new locations as wood chip mulch has become more common. The psilocybe allenii mushroom doesn't look nearly as strange as the basket stinkhorn, but its molecules do things that are much more bizarre.

The bluing on these mushrooms is caused by a molecule called psilocybin. When humans consume psilocybin, it affects our brain activity dramatically. Some functions, such sense of self, sense of time, and planning, are suppressed. Other functions, such as sensory perception, emotions, and connections between disparate parts of the brain are enhanced. This can feel like epiphany, access to a previously-hidden world. People may experience hallucinations, nausea, inability to move, and/or the giggles. It can be confusing, beautiful, frightening, pleasurable, hilarious, sad, or all of the above. Many people report that a single experience changes their perception of the world permanently. Medical research has shown great promise for combining talk therapy and psilocybin to treat addiction, depression, and anxiety. 

No one knows for certain how or why this molecule evolved, but it may have evolved as part of fungi's battles with bacteria or insects. One fungus uses the psilocybin it produces to dope cicadas and cause them to spread the fungus's spores.

What could be more banal than a bare patch of landscaping wood chips? We spread them outside schools, banks, and strip malls. They are meant to discourage weeds from disrupting tidy in-between spaces. But those wood chips hold potential energy in their organic molecules, a resource that will not remain untapped and undisturbed. Strange creatures spread their thread-like bodies, eating and growing. They send forth their fruiting bodies, flush with weird molecules that attract insects and assault our noses, or that fight insects or bacteria and alter our brains and our understanding of the world.

LINKS

article about basket stinkhorn from Bay Area Mycological Society

article about psylocybin medical research from the New York Times

How to Change Your Mind by Michael Pollan

article about psylocybin and cicadas from Science Daly

Map of the UC campus

Return of the Ruby-crowned

We paddle our canoe across Tomales Bay in the drizzle, going in the morning to avoid the usual afternoon winds that kick up the waves. We spend a chilly day sitting by the fire; paddling along the shore; watching loons, tule elk, river otters, osprey, and even a bald eagle. The next morning I wake up to bright sunshine and grab my binoculars and camera. The trees along our small beach are alive with song birds. A tiny, bold bird with a white eye ring and wing bars hops through the hanging moss, coming quite close to me. It's a ruby-crowned kinglet, one of my favorite signs of fall.

Then back in Berkeley over the next few days, I see them everywhere: outside my office in a scrubby little live oak, and another in the juniper bushes by the parking lot.

Then a few days later on my regular bird walk in Tilden Park near Jewel Pond:

And even in my front yard:

You might notice that there are no ruby crowns in these photos. Only the males have red patches on their heads, and even they keep them hidden most of the time. They flash them to signal to a potential mate, or a potential threat.

These lively little birds are quite common in our area from fall through early spring, but then they all migrate to Canada or to high elevations in the Sierra Nevada and the Rockies to breed and nest. In summer, these kinglets are fairly specialized, spending most of their time high in conifers and eating only insects. During migration and in winter, they are more of generalists, living in all kinds of trees and bushes, and adding fruits, berries, sap, and nectar to their diet.

It is likely that the ancestors of migratory birds like these originally spent all their year in what is now their winter habitat. Later they evolved to migrate to their breeding grounds. There are huge disadvantages to migrating: most obviously, the massive energy expenditure to travel that far, but also the requirement to add evolve a new set of behaviors to suit the new, second environment. There must, therefor be an even greater advantage to this adaptation that outweighs the costs. It is likely that this advantage comes from reduced competition for food and nesting sites in areas that are too cold to support most bird species during the winter. Migration behaviors probably evolved gradually, with birds initially traveling shorter distances.

The details of ruby-crowned kinglets behavior during nesting season are not well known. It spends its summers high in tall trees, in relatively unpopulated areas. This bird that is so bold and common here in its winter home becomes mysterious each summer.

LINKS
Ruby-crowned kinglet information from the Cornell Lab of Ornithology
Ruby-crowned kinglet information from Audubon
Tilden Regional Park

Chicken of the Woods and Eucalyptus

The air is dry, with a crisp edge, and buckeye leaves are yellow husks that rustle under foot. Our trail take us into a eucalyptus grove. Strips of fallen bark from the trees cover the ground and lean haphazard against the stripy trunks of the trees. And there, sticking out about ten feet up on one of those trunks, is what we are looking for, a pile of rounded yellow shelves: chicken of the woods. This is the first edible fungus of fall here in the East Bay.

We prod it with a stick and it turns out to be a bit too old and hard to eat, but soon we spot a clump on another tree. It is spongy and moist. Beads of liquid wet our hands. Dinner!

Chicken of the woods, also called sulfur shelf, is a parasitic fungus that feeds on living trees or fairly recently cut stumps. It takes nutrients and moisture from its host. The organism lives within the wood all year long, as a tangle of threads called mycelium. The yellow shelves we picked are the fruiting body, which grows in autumn and releases spores to reproduce. The fruiting body appears so early in the fall, often before any significant rain, because it doesn't rely on moisture directly from recent rain. As the fungus spreads through the tree, it makes the tree more brittle. The tree may eventually fall when it becomes too brittle to bend with the wind.

This species of chicken of the woods (Laetiporus gilbertsonii) grows mostly on oak and eucalyptus in our area, though I have have only seen it on eucalyptus. Eucalyptus trees are not native to California; they were brought from Australia in the 1850's by Australian settlers. In the early 1900's, unscrupulous boosters sold plots of land planted with eucalyptus (mainly a species called blue gum), promising easy money from timber from the fast-growing trees. In just a few years, millions of trees were planted. But this species makes for terrible timber. Most of the stands of eucalyptus are abandoned crops from that era; they don't reproduce well enough in most parts of California to be able to spread to new areas. These eucalyptus groves pose fire hazards, since eucalyptus is extremely flammable. And they don't support many native species. Chicken of the woods is an exception: a California native that thrives in eucalyptus.

Laetiporus gilbertsonii

Another local species of chicken of the woods (Laetiporus conifericola) grows only on conifers,  such as douglas fir.

Laetiporus conifericola

The gilbertsonii chicken of the woods tastes like chicken, meaty and rich, which is how it got its name. The conifericola chicken of the woods has some of that flavor but also has a very strong sour taste. I like it, but some people don't. People's reactions to eating chicken on the woods vary, and not just in relation to the taste: it makes some people projectile vomit! It may be that long cooking reduces that possibility. I sautee it in butter or oil for about five minutes, simmer it in wine and water for another 25 or 30 minutes, cross my fingers, and enjoy.

As chicken of the woods fungus age and get too hard and chalky for people to eat, they are often munched by potato bugs (aka pill bugs, roly-polys) or beetles. Eucalyptus have been in our ecosystem for almost 200 years now. They aren't as deeply entwined with other species as native trees are, but they are a part of our food webs, connected to fungus, people and bugs. Herons and egrets sometimes nest in them. The other day I spotted a red-breasted sapsucker feeding in one. I wonder what new relationships will develop in the next thousand or ten-thousand years.

Even as some stands of eucalyptus are removed to reduce fire danger and to make space for native vegetation, we will continue to live with this species, and with the strange, delicious fungus that attacks it.

LINKS:
Bay Area Mycological Society article about chicken of the woods
One KQED article about eucalyptus in California and another

Mixed Flocks in Fall

"Ka dee dee dee! Chwee deee dee!" The cheery squeaks of a chickadee make me stop and scan the trees. Perky, feathered balls are on the move, popping along the outer branches, hanging upside down to snag a bug.

For a couple of minutes, chickadees are the only birds I see—cute for sure, but also common and not that exciting. Then, a movement catches my eye that registers as different. I look through binoculars, and yes, a bright yellow face streaked with black: a Townsend's warbler.

The longer I stand there, the more movement I see all around. I spot a brown creeper, working its way up the trunk of a large oak, perfectly camouflaged with the bark.

Towhees kick up the leaf litter. Bushtits mingle with the chickadees. A pacific-slope flycatcher flutters out from a branch and back to its perch.

Forest birds often travel in mixed flocks like these. I first learned about this phenomenon in the rain forest in Costa Rica, but it's common here in the Bay Area as well. Mixed flocks allow birds the benefits of foraging in a group—more eyes and ears to spot danger—with less competition for food than there would be in a flock of just one species. Chickadees gather bugs and seeds mostly from small branches and leaves. Flycatchers grab flying insects out of the air. Towhees find their food on the ground.

This is an especially good time of year for watching mixed flocks because our resident birds, such as chickadees, towhees, and creepers, are joined by migrants on their way south, such as Townsend's warblers. Townsend's warblers nest in conifer forests of western Canada and the Pacific Northwest. Some winter in a narrow band along the coast from Washington to Baja, but most travel on to Mexico or Central America. Their lifestyle changes quite a bit in different parts of their year: in nesting season they live high in old-growth conifers forests, eating mostly insects. During migration they come lower in branches of all sorts of their trees, and eat a lot of flower nectar. In winter in Mexico and Central America, many guard trees infested with scale insects that secrete a sugary liquid that the birds eat.

I wonder why the mixed flock behavior evolved for some species but not others. When I notice chickadees, I always scan for other species, but dark-eyed juncos—another of our most common forest species— almost never seem to join mixed flocks. I wonder how a mixed flocks joins together. Do the birds happen upon each other by chance and just stick together? Do they seek each other out using calls? Or start the day in the same area each morning?

Each time I happen upon a mixed flock, the mix of species is different. While chickadees are almost always a main ingredient, sometimes oak titmice, bushtits, or ruby-crowned kinglets form the nucleus. The mix may include woodpeckers, nuthatches, or vireos. A mixed flock is a dynamic and eye-catching example of the interweaving—through competition, cooperation, and micro-habitats—of different species in any ecosystem: the mix of live oaks, bay trees, and ferns along the seasonal creek bed in the canyon outside my work; the spring collage of lupine, poppies, and checkermallow by Volmer Peak in Tilden Park.

LINKS:
Washington Post article about mixed flocks on the east coast
Cornell Lab of Ornithology Information about:

• Chestnut-backed chickadee
• Townsend's warbler
• Brown creeper
• Pacific-slope flycatcher

Tropical Nature: Life and Death in the Rain Forests of Central and South America, a wonderful book where I first read about mixed flocks

Bluebird Families in San Pablo Park

I walk the two blocks from my house to San Pablo Park. The birds I'm looking for are right there to greet me, perched on the surveillance camera sign at the edge of the park. Their heads are soft grey, their chests rusty orange flecked with white. Their tails flash cornflower blue. They have a bit of a shaggy look, ends of fluffy, white feathers peaking out on their chests and bellies. These are juvenile western bluebirds. As I walk through the park, I see them on the fence by the tennis court, bathing in the drinking fountain, perched in the chestnut trees, flycatching in the grass by the toddler playground.

Western bluebirds are cavity nesters. They nest in holes in trees made by woodpeckers, or in nest boxes put up by people. They are not normally seen in cities. Non-native, city-loving birds such as house sparrows and starlings usually out-compete bluebirds for nesting spots in cities. Until 2008, bluebirds were extremely rare in Berkeley. That was when Rusty Scalf, a local birder, discovered a pair nesting in San Pablo Park.  We moved to our house by the park that same year. I remember the jolt of pleasure and surprise when I first spotted the bluebirds. The color is so distinctive and bold and had been so firmly associated in my mind with grassy wild-lands like Briones park.

Scalf worked with the park department to install nest boxes, and our small, unusual bluebird population expanded. Now I see them around the neighborhood, not just in the park. One year, a pair even nested in a box in the oak in our front yard. Over the spring and summer, a pair of bluebirds can raise up to three broods of young, with 2-8 birds per brood. Some pair are helped in raising their young by single adult male birds or other pairs without their own nests. This time of year—the end of the summer—the park is aflutter with juveniles. I like to imagine them venturing out through our neighborhood, searching for holes in trees, finding the best fences to catch moths and flies from.

I wonder what is allowing this bluebird population to thrive in Berkeley. There are certainly plenty of house sparrows and starlings here that might compete with them. Have they developed some behavior—perhaps related to the nest helpers—that allows them to fend off the sparrows and starlings? Could they be passing on this behavior as local cultural knowledge? Such passing on of novel behaviors has been documented in certain crow populations, though not as far as I know, among bluebirds. Could there be a genetic difference that allows our birds to survive? Something that allows them to use holes not used by other birds? Could we be witnessing a small example of natural selection? Or is it a matter of chance? If so, perhaps our population will not last. Whatever the answer, it is rare, beautiful, and right around the corner from my house.

LINKS:

Golden Gate Audubon blog post about the Berkeley bluebirds

Berkeleyside article about them

Western Bluebird information from the Cornell Lab of Ornithology

Buckeye Butterflies: Color and Complexity

I step away from my computer at the Lawrence Hall of Science, and cross the parking lot to the open hillside, overlooking the bay. The grasses are crackly, bleached, and bristling with sticky burrs and seeds that attach to my socks and leg hairs. I stand blinking in the bright. A pair of butterflies fly up from the grass, circling each other, and disappear over the oaks. Another butterfly crosses in front of me and lands. It is soft brown, with pale shades of orange and yellow. It has six striking black circles on its wings. A common buckeye. I stand watching and spot many more. Whenever two encounter each other they spiral off in a chase.

Some have significant pieces of their wings missing.

Many sources say that the males are territorial: that the chases I saw were males claiming their patch of the hill. If so, how do they determine which one is the winner? How far away does the loser go? On the other hand, James Scott writes in The Butterflies of North America: A Natural History and Field Guide, "Although the male behavior of chasing passing objects looks pugnacious, males are not truly territorial but merely looking for females." If this is the case, I wonder what purpose the furious, spiraling flight serves. A test of fitness before a mate is accepted?

The larva are bristly black caterpillars with orange bumps. The bumps may serve as a warning to potential predators. One of the larvae's primary foods is the narrowleaf plantain. This plant has a molecule that inhibits growth in predators such as wasps, and and birds, though it increases growth in the caterpillars. Buckeye larvae that eat more plantain are less likely to be eaten by predators. Apparently, this protection does not extend to the adult butterflies, which are frequently eaten by birds. The missing chunks I noticed from their wings were probably from beak attacks.

In the bay area, buckeye butterflies can hatch at any time of year, but most hatch from mid-summer to early fall.  They evolved from tropical species and cannot withstand severe cold no matter what life stage they are in. They were nearly wiped out in the bay area during an extremely cold week in 1990, then gradually recolonized our area. The appearance of the common buckeye vary depending on what time of year they hatch. Those born in winter or early spring are much smaller. Those born from late August through October have a purplish or brick-red underside, while those that hatch at other times are much paler. The genes controlling color in the buckeye are complex-- coding both for pigments as well as nanostructures that refract light and create iridescence. No one knows exactly how changing hours of daylight and temperature affect the expression of these genes.

As I watch the buckeyes, a speck of blue flickers on and off: the acmon blue has bright blue upper wings, but pale grey underwings. It is not much bigger than my thumb nail.

The field crescent has a similar color pallete as the buckeye, but in a stained-glass checkerboard.

At first glance, a grassy hillside in bay area summer appears fairly simple and monochromatic, but a world of color and complexity is revealed by the butterflies there. The orange bumps on a buckeye larvae hint at struggles and evolution among buckeyes, birds, ants, and plants: a contest at the scale of molecules. The changing shades of the buckeye wings mark the slow shift of the seasons, and hint at connections between the orbit of our planet and the genes in the butterflies' cells.

LINKS
Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Region (fabulous field guide and the source of much of the information in this post)
Art Shapiro's Butterfly Site (online butterfly guide from UC Davis)
       Buckeye page
The Lawrence Hall of Science (butterfly habitat outside, science museum- and my desk- inside)
The Butterflies of North America: A Natural History and Field Guide