A very special announcement… Wild Oakland is joining forces with the California Center for Natural History!

For upcoming events and new blogs, everything can be found at the California Center for Natural History website. Keep reading for more information about the changes!

Hi Everyone,

I’m very excited to announce that as October 2015, Wild Oakland has become part of the California Center for Natural History! This means even more free events & other fun stuff that we’ll be able to create for the community! I’m sure you have some questions, so I’ve done my best to anticipate and answer some below:

What the heck is the California Center for Natural History?

Earlier this year, Constance Taylor (the founder of Wild Oakland) and other naturalists decided to create a coalition of environmental educators to share resources & work together to bring even more awesome natural history programming to Oakland and the Bay Area. That coalition decided to call itself the California Center for Natural History, or CCNH!

Many of the people involved in CCNH have led walks for Wild Oakland in the past, and all of us feel that providing accessible natural history education for adults & families is a great way to strengthen our human community as well as learn more about the non-human world around us.

Since CCNH members have been working together to provide programming, we’ve managed to quadruple what Wild Oakland was able to do alone. In September & October we provided 8 events total, and 5 of those events were totally free!

Our fee-based events are so we can pay our naturalists to teach programs, and keep our operations going. At the moment we all have other jobs to pay our bills- CCNH is a collective labor of love!

Will there still be free events?

Absolutely- we’ll always have at least 1 free event per month, if not more- in the past 2 months alone we’ve had a whopping 5 free events!

We’ll also be increasing the number of fee-based programs so we can pay our naturalists for their expertise. Fee-based programs will have the added bonus of a limited group size; the crowds at free events can be pretty large, so for a few extra dollars you’ll get the luxury of a much smaller group and more one-on-one time with the naturalists.

What will happen to Wild Oakland?

We’ll be keeping the Wild Oakland website and name for archival purposes (you’ll still have access to our 3+ years of blogs about Oakland’s ecology), but from now on you’ll be receiving e-mails only from CCNH.

Will I have to sign up for the CCNH mailing list if I’m already on the WO mailing list?

No. If you’re already on the WO mailing list, it will be rolled into the CCNH mailing list. However, you’ll want to make sure the CCNH e-mails aren’t going straight into a spam or “Social” folder.

If you want to opt out at any time, it’s really easy- all you have to do is click the “Unsubscribe” link at the bottom of the e-mail.

Can I help out CCNH?

Absolutely! We’d love to have you on board. We need volunteer photographers, blog writers, grant writers, a bookkeeper, and fundraisers. If you’re interested in any of these positions, or if you have other ideas, let us know at ccnhinfo@gmail.com

Where can I learn more?

Check out our website at www.calnature.org, like us on Facebook, and follow us on Twitter and Instagram. And of course, come to the events!!

Thank you all so much for your continued support over the years. We’re very excited to be moving into this new instar of our development, and we’re so happy and grateful that you’re part of the adventure.

We’ll see you out there!

Constance Taylor
Founder & Executive Director of Wild Oakland

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Franciscan Geologic Formation at Knowland Park

By Birute Skurdenis

“To look at the geology of Oakland is to look at the geology of California and the planet.” A group of Wild Oaklanders was standing in the shade of an old oak listening to Andrew Alden, geologist, talk about the geology of Knowland Park. Standing on a large flat knoll at the southern end of the park, we were rewarded with sweeping views of the East Bay with San Francisco and the Peninsula in the distance.

An unusual flat knoll at Knowland Park. Photo: Constance Taylor

An unusual flat knoll at Knowland Park. Photo: Constance Taylor

Knowland Park is one of those rare urban places not covered with homes and concrete, where it’s possible to see relatively undisturbed landscape. Most of Oakland consists of ridges, so this flat knoll is a mystery that geologists have pondered but have never come up with a complete explanation for why it’s here.

We were standing on the Franciscan formation, a geological term for the mixture of oceanic rocks found along the California coast and especially in the San Francisco Bay Area. Franciscan formation rocks were churned in the ocean trench where the Pacific Plate meets the North American plate. They were added to the North American continent by the motion of plate tectonics, the same motion that bring us earthquakes along the San Andrea and Hayward faults. We couldn’t see most of the rock underneath our feet because of the dirt covering it, but Andrew introduced us to “knockers.” These above ground rock formations are larger than boulders, which Andrew likened to “plums in the pudding of the landscape.” In the case of Knowland Park, the pudding is a mix of fine grained shale and sandstone. While some of the rocks of Oakland originated 150 million years ago (you can find them in the Leona Quarry area and in other parts of Knowland Park,) the rocks here were only about 60 million years old.


Wild Oakland_knowland park knocker

wild oakland_andrew talking

Three knockers at Knowland Park.  The last formation is one that "geology students usually have to travel miles and miles to find- it's pristine! No construction scarring, no graffitti- it's very unusual to find an outcropping that's this undamaged", says Alden. Photo: Constane Taylor

Three knockers at Knowland Park. The last formation is one that “geology students usually have to travel miles and miles to find- it’s pristine! No construction scarring, no graffitti- it’s very unusual to find an outcropping that’s this undamaged”, says Alden. Photo: Constance Taylor


The Oakland hills are dotted with old quarries, created by mining materials for road beds and land fill. I find it fascinating to think that the site of Bishop O’Dowd High School, Head Royce School and the 51st and Broadway shopping center are all old quarries.

From the top of Knowland Park, Andrew pointed out where the Hayward fault lies at the foot of the hills, cutting through the Knowland Park Zoo parking lot and extending north through the UC Berkeley campus and into the Bay at Point Pinole.

Being among Wild Oaklanders has the added benefit of being among knowledgeable nature lovers. Members of the California Native Plant Society talked about the Park holding remnants of Bay Area Prairie while other Wild Oaklanders filled people in about the Oakland Zoo’s expansion from its historic position below, near Highway 580, to the ridge near where we stood.

Easy access to Knowland Park is at the end of cul de sacs off Malcolm Avenue. Most have small parking areas and paths into the Park.

People who are interested in learning more about the geology of Oakland should check out Andrew Alden’s blog https://oaklandgeology.wordpress.com and Doris Sloane’s excellent Geology of the San Francisco Bay Region, which is available from UC Press and can be ordered at your local bookstore.

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An Afternoon with Worms, Snails and Sea Squirts

By Paul Belz

Checking out what's living under the dock! Photo: Jerrie Reining

Checking out what’s living under the dock! Photo: Jerrie Reining

Few things beat an afternoon with animals that have no backbones! Damon Tighe, an invertebrate enthusiast who lives near Lake Merritt, guided a group of explorers on a sunny September afternoon. The Lake’s different concentrations of salt and of dissolved oxygen give homes to creatures who have come here from all over the world. The Lake is brackish, meaning that freshwater that flows from streams in the hills & mixes with saltwater from the Bay. The salt content in the water makes it uninhabitable for dragonfly nymphs, crayfish, and other freshwater invertebrates.

Damon shared creatures he’d collected and placed in tubs of water. “Because we’re so close to the Port of Oakland, the majority of organisms you’re going to see today are not from California,” he said. Native mussels do thrive in large clumps on the Lake’s docks, where the oxygen concentration is high. Damon shared a local yellow shorecrab (Hemigrapsus oregonensis) and described sea hares, which are large sea slugs. “They can be as big as a rugby ball, or a small rat,” he said. These interesting creatures have been seen in big numbers this summer near the floodgate that separates the Lake from the Bay.

Oriental shrimp (Palaemon macrodactylus) thrive in low oxygen regions along the Lake’s edges. “If you come through at night with a UV light, you’ll find them, Damon said. “They fluoresce under the light, kind of like scorpions.”

“But less harmful,” an young girl commented.

Eastern mud snails (Ilyanassa obsoleta). Photo: Damon Tighe

Eastern mud snails (Ilyanassa obsoleta). Photo: Damon Tighe

“And probably more tasty,” Damon laughed. He described eastern mud snails (Ilyanassa obsoleta) from the Carolina oyster beds that also live in this harsh habitat. They crawl over the bodies of creatures that have died, and feast on them.

Dead mans fingers (Halichondria-bowerbanki). Photo: www.seawater.no

Dead man’s fingers (Halichondria bowerbanki). Photo: www.seawater.no

Dead man’s finger is a sponge (Halichondria bowerbanki) that looks like a yellow, shriveled up hand when it grows large. Sponges, the world’s simplest multicellular animals, spend their lives attached to rocks or other hard surfaces. A sponge doesn’t have real tissues or organs; rather it is a collection of cells working together to survive. Collar cells move their whip like flagellums to make water flow into the sponge’s many pores, and gather bits of food on their sticky surfaces. Other cells move the food through the pores so all parts of the animal gets to eat. “You can put a sponge in a blender and turn it on,” Damon said. The cells given time will gather back together to form a sponge again,”

A segmented worm (Typosyllis nipponica) slid quietly through the tub of water. At a certain point, this animal’s tail changes from green to an orange color, breaks off, develops eye spots, and swims away. These epitokes are sacks of gametes, or sperm and eggs. “They’ll swim and gather together and start popping,” Damon said. They release their sex cells and produce their young this way. People in Hawaii love to eat epitokes of some of their native polychaetes

Damon shared two oyster drill snails (Urosalpinx cinerea)whose ancestors came from the Carolina oyster beds. The pair had settled on a mussel, and seemed to be about to mate. Later, they would drill into the mussel and use their proboscises to feast on it. The group later found drill snails’ egg cases, which one hiker said looked like passionfruit seeds.

Sea squirts, or tunicates, are some of the strangest of the Lake’s critters. These animals have notochords, bundles of nerves that function as primitive spines when they are in their young, free swimming stage. As they age, these filter feeders settle to rocks, and their notochords wither away. Now they absorb and release water, eating the small living things they can grab. These odd animals are ancestors to all vertebrates, including humans. Damon touched one and showed the group how it squirts water, getting its name from this activity.

Damon mentioned that the many invertebrates in the Lake form the basis of its food web. Gulls can easily feast on these dark shelled mussels when hot temperatures and low tides cause them to dry out. Yellow finned gobies and other fish eat the spineless ones, and become prey to the Lake’s birds. “We saw a cormorant eating a pipefish, a relative of seahorses, when we got here,” Damon said. Birds also feast directly on invertebrates. The Lake’s complex food web explains why so many birds make it their home.

Discovering things at Lake Merritt. Photo: Jerrie  Reining

Discovering things at Lake Merritt. Photo: Jerrie Reining

Bat rays and leopard sharks, which eat mussels and clams, sometimes come into the Lake from the Bay. The otter that was spotted once has not been seen again but it could return. Damon hoped that more Bay invertebrate and other animals would enter the Lake as the connections between the two water bodies are improved. Keep watching the Lake, you never know what weird treasures you’ll find!

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Land Action: Creating 100 Microfarms in 5 years

Land Action microfarm at 37th and West streets in Oakland. Photo: Land Action

Land Action microfarm at 37th and West streets in Oakland. Photo: Land Action

By Constance Taylor

What’s a city to do with abandoned lots? If you ask Steve DiCaprio, CEO and founder of Land Action, he’ll probably tell you they should be turned into microfarms with tiny homes on them. We had gathered to see the first of the microfarms Land Action created, a corner lot on 37th and West street.

Many years ago, this land had a single-family house on it. After the original owned passed away the title was handed over to a family member, who promptly stopped paying the property tax or doing any maintenance. The house remained neglected for many years, with the city imposing fine after fine on the owner for blight. The city eventually became responsible for the property and tried to sell it at auction multiple times, but couldn’t start the bids at any less than $650,000, which was what was owed on the property in back taxes and fines. Needless to say, no one was interested in paying over a half million dollars for a dilapidated structure in a neighborhood that was having serious troubles with the drug epidemic of the 1980’s.

About 15 years ago, the city tore down the house and sent the owner a bill for $100,000. After that the city would contract people to “mow and blow” the area once a year, which meant that someone would come in once a year to chop down the chest-high weeds that had sprung up. Unfortunately, this clear-cutting would send the many rats living in the tall vegetation scurrying for cover, often finding their way into the surrounding houses! The area had also become a trash dumping ground, littered with everything from syringes to mattresses.

Nearly 5 years ago, Steve and a friend breached the fence surrounding the property and started gardening. Since then they’ve made a deal with the City of Oakland to maintain the property- the city no longer has to pay contractors to come in and mow the lot, and Land Action was able to start their microfarm.

Steve DiCaprio takes us into the chicken coop. Photo: Constance Taylor

Steve DiCaprio takes us into the chicken coop. Photo: Constance Taylor

The lot has a number of fruit trees, raised bed gardens, chickens, and ducks. Urban farming, of course, has it’s challenges- “We were given some chickens that had gentle tempers, but unfortunately, raccoons managed to get into their coop and ate them,” Steve explained. “Since then, we ended up getting some Rhode Island Reds [a breed of chicken] that some folks didn’t want because they’re far more aggressive than most other chickens. But for us, that’s perfect! We’ve made the coop more raccoon-proof, but if something happens we’re hoping these chickens will be able to fight back.”

Steve also mentioned how they work within the limits of their environment, especially with the drought. “There was some push and pull within the collective this year about whether or not we should even plant anything because of the water shortage.” Since people don’t necessarily depend on this particular garden for produce, they decided to scale back this year to save water. “Right now the only water we use for the plants is from the duck pond when it needs to be cleaned, which is why it’s looking a little brown around here.”

Currently, Land Action is pushing for 100 microfarms in Oakland in the next 5 years. They’re currently fundraising to cover their administrative costs- to learn more about Land Action, the microfarm movement, and how you can get involved, visit their website!

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Marine Biology of the Oakland Estuary

By Birute Skurdenis

Checking out the floating docks! Photo: Jerrie Reining

Checking out the floating docks! Photo: Jerrie Reining

If you were strolling on the boardwalk behind Scott’s Restaurant in Jack London Square on September 12th, you might have come across the odd sight of 2 dozen people of all ages, lying on their stomachs on the floating dock below the restaurant, peering into the water. Armed with plastic containers of all sizes and a variety of magnifying lenses, this was the Wild Oakland Marine Biology Tour. Led by Ken-ichi Ueda, founder of iNaturalist, we were going to see what lived under the boat docks of the Oakland Estuary.

Ken-ichi explained that because the estuary is a heavily used international ship channel, the marine biology in Oakland’s ports is a lot more exotic than what you might find in other coastal waters. Biological hitchhikers find their way to San Francisco Bay waters just as many of us humans have. While many of these non-natives are relatively benign, some, like the shipworm, a clam that bores into wood, can cause millions of dollars worth of damage to man-made structures in the Bay. A well-maintained dock requires a regular scraping of the accumulated biological build-up to preserve its integrity.

Guide to the some of the organisms of Jack London harbor, created by Ken-ichi Ueda

Guide to the some of the organisms of Jack London harbor, created by Ken-ichi Ueda

While some folks had brought their own containers, Ken-ichi supplied us with a photo card and some plastic bowls and challenged us to dip into the water under the docks to find the 9 creatures on our card: skeleton shrimp, bryozoan, sea squirts, yellow sponge, scale worms, feather duster worms, brittle star, sea slugs and Bay pipefish. Soon words like ‘nudibranch’ (the “ch” is pronounced like a “k”,) ‘tunicate’ and ‘stylidae’ were flying around. There were a few people who were familiar with what we were looking at and helped the rest of us identify what we were pulling up from the Bay.

We dipped our containers and started looking. My personal favorites were the brittle stars (Ophiuroids), which are related to starfish. As we found them in the Oakland Estuary, they were small (1/4 “ – 1/2 ”) organisms with a tiny round center and 5 stick figure “arms” that moved like those of an octopus. If you were lucky enough to pull them up from the water, you could watch them use their arms to swing around your container like miniscule monkeys.

Some folks brought up big clumps of seaweed, algae, mussels and sponge and picked it all apart to see what it contained. The chains holding the floating dock in place were a good place to start a search. One of the more elusive creatures on our “to find” list, was the sea slug, or nudibranch. Those we found in the water that day were very small, 1/8” to1/4” in size and, to the untrained eye, looked like a piece of algae debris. With a hand lens, however, you could make out the antennae and slug body. Fortunately, the sea slugs were often found together with bryozoa, an easily identified organism (or more correctly, a colony of organisms) with a distinctive branch-like structure that looked like fine blood veins or plant roots.

Pipefish. Photo: Ken-ichi Ueda

Pipefish. Photo: Ken-ichi Ueda

Another creature we looked for was the pipefish and were excited to find tiny juveniles, no more than 1” long until someone pulled a 6” pipefish out of the water. It’s a relative of the sea horse, with a long, eel-like body and sea horse-like head, and. like the sea horse, the males raise the eggs in a pouch on their belly.

Collectively, we found everything on our photo cards. Everyone, young and old, got a big kick out of discovering this unknown, aquatic world in our own back yard. So find a public dock, get down on your belly and take a look.

For more photos and information about marine biology of the Oakland Estuary, see the Wild Oakland blog from last year!

Here are a few pictures of what we found:

Clockwise from top left: Hedgpeth's Dorid (Polycera hedgpethi), flatworm (Phylum Platyhelminthes), Feather duster worm (Genus Branchiomma), sponge (Phylum Porifera), Dwarf Brittle Star (Amphipholis squamata), worm (Family Nereididae). Photos: Robin Agarwal

Clockwise from top left: Hedgpeth’s Dorid (Polycera hedgpethi), flatworm (Phylum Platyhelminthes), Feather duster worm (Genus Branchiomma), sponge (Phylum Porifera), Dwarf Brittle Star (Amphipholis squamata), worm (Family Nereididae). Photos: Robin Agarwal

No need for fancy equipment here! Wild Oaklanders examine sea life using a plastic cup. Photo: Wanda Ng

No need for fancy equipment here! Wild Oaklanders examine sea life using a plastic cup. Photo: Wanda Ng


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The ecological price of overgrazing

By Constance Taylor

When I first moved to the Bay Area 6 years ago I was mystified by the tracks that contoured the hills in the regional parks. From a distance it looked like a diligent landscaper was out there with a lawnmower, riding in circles around the hillsides and creating neat, concentric lines from the top to the bottom of the slopes.

After wandering around the East Bay Regional Parks and seeing lots of cow poo (as well as lots of cows), I finally figured out that the ‘lawnmower tracks’, officially called ‘terracing’, were made from cattle, who prefer to walk around and around in a spiral to get to the top of a hill rather than walk straight up the side. This, of course, led to more questions, like what effect the grazing and soil compaction have on the ecology of these areas.

There’s a decent amount of conflicting information out there about what cattle grazing does to the environment. If you do a Google search involving the words ‘cattle’ and ‘ecology’, wildlife biologist Allan Savory will pop up at least once in almost every set of results. For years he’s pushed his hypothesis of “holistic management”, in which grazing livestock mimics large groups of wild animals, such as buffalo and elephants, traveling through deserts and grasslands. The idea is that if ranchers carefully manage their herds, they can not only increase their numbers of livestock but also reverse the effects of climate change. Savory’s claims have been widely criticized by ecologists because of lack evidence supporting his conclusions, but the idea that managed grazing can have positive ecological impacts, including benefitting threatened species, is alive and well.

Sailesh Rao, founder of Climate Healers, has been educating people about the correlation between cattle grazing and climate change for 10 years. Though he works mostly in India on these issues, he also spends time in the Bay Area and works on parallel issues in the U.S. As we walked through Wildcat Canyon and watched the cows placidly laying under whatever shade they could find, Sailesh gave us a broad-strokes overview of how he sees things.

With a background in systems engineering, it’s in Sailesh’s nature to look for the most logical, efficient way to do things. “After looking at the issues of climate change, the biggest systems problem ever, it’s clear that nature is the best systems designer out there- far better than we are!”

Some general examples include intact, native ecosystems being better at carbon sequestration then heavily grazed areas, and plant-based diets being a far more efficient way to feed the 7 billion people on the planet. “It takes nearly a thousand gallons of water to produce 1 gallon of milk, about 45% of the earth’s landmass is used for livestock grazing, and animal agriculture is a major cause of habitat destruction, ocean dead zones, and species extinction… how is any of this sustainable?” Sailesh asked.

Sailesh was already a vegetarian before he began his work on climate change, but became vegan after studying the effects of free-range grazing both in India and in the U.S. “You see ‘free-range’ and ‘grass-fed’ on meat and dairy products, but what that really means is cows are out there eating everything and creating an ecological disaster zone.” For those interested in learning more he recommended watching ‘Cowspiracy‘, a well-reviewed documentary about animal agriculture with a focus on the beef industry. You can watch it on the Cowspiracy website, or after it comes out on Netflix on September 15, 2015.

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Urban Wildlife 101

By Constance Taylor

There’s an admiration that many of us have when it comes to urban mammals. Where do they sleep? Where do they raise their families? How do they find enough food to eat? How do they avoid cars, dogs, rodenticides, and any other potentially lethal obstacle they face daily when living around thousands of humans?

Lila Talcott Travis. Photo: Lee Aurich

Lila Talcott-Travis. Photo: Lee Aurich

Lila Talcott-Travis from Yggdrasil Urban Wildlife Rescue came to talk about this (and more!) during our “Urban Wildlife Survival 101” event, with a focus on mammals. But first, what do we mean by urban? “Today we’re defining ‘urban’ as areas that have been heavily modified to suit the needs of humans above any other animal,” Lila defined. Challenges for wildlife can include those listed above as well as light & sound pollution, and separated open spaces.

Storm drain inlet. Photo: www.dot.ca.gov

Storm drain inlet. Photo: www.dot.ca.gov

“Some animals spend their entire lives in one park because it’s surrounded by roads that they don’t want to cross,” Lila explained. “Of course, some of them do cross the road, which can result in a grisly end.” Some species have, however, figured out ways to use city infrastructure to avoid many dangers. Raccoons, opossums, and skunks will often use storm drain inlets on the sides of roads as entrances to man-made underground tunnel systems to travel from place to place, and squirrels will use telephone and electrical wires to avoid things like dogs, cars, and people. Other animals, like coyotes, might not fit down a street-side storm drain opening but other aspects of the human-built environment work to their advantage. Food waste in garbage cans, sprinklers & leaky pipes providing convenient water sources, and a lack of predators or other competitors can provide easier living conditions for urban mammals. “Interestingly, coyote pups that live in cities have higher survival rates than in rural areas,” Lila mentioned.

Wildlife crossings are one aspect of urban living that might point to our willingness to give other species a leg-up in our built environment. Closing roads for wildlife during migrations, like at Tilden Park for the California newt breeding season, is certainly one solution. Other places have decided to create separate infrastructure for animals, such as the California tiger salamander tunnels in Sonoma County, vole bridges in London, or the multitude of wildlife crossings in Banff, Canada.

Two baby squirrels. Photo: Lee Aurich

Two baby squirrels. Photo: Lee Aurich

Lila had also brought some baby animals she’s currently rehabbing for release back into the wild. If you’ve come on one of Lila’s Wild Oakland walks before, you’ve probably seen the baby squirrels she brings! This time, however, in addition to the baby squirrels she also brought two baby opossums.

“Opossums are really amazing animals,” Lila told us as she held one up for us to see. They’re the only marsupial in North America, and research suggests they were around during the time of the dinosaurs! In fact, North America is thought to be the origin of all current-day marsupials. If you’re worried about getting rabies from an opossum, rest assured that it’s highly unlikely- the body temperature of opossums is too low for rabies to survive and replicate. People sometimes think that if an opossum is drooling it’s because it has rabies, but it’s really just a defense mechanism. When threatened they’ll open their mouth to show all 50 of their teeth, and start drooling. They might nip at whatever is frightening them, but they won’t start lunging and attacking- it’s just not how they’re wired! If that doesn’t work, then they play “possum”- they’ll collapse, their bodies will stiffen, and they’ll start oozing nasty-smelling secretions to smell like decaying meat. Playing dead is really quite effective against predators, but unfortunately, not so good when it comes to cars. Maybe Oakland should install some opossum corridors around the city…

Lila holds a Virginia opossum. Photo: Lee Aurich

Juvenile Virginia opossum. Photo: Lee Aurich

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Oakland Geology with Andrew Alden at Shepherd Canyon

By Constance Taylor

So, we all know about the Hayward Fault. If you didn’t grow up somewhere around Oakland learning about it while doing earthquake simulations with trays of jello in science class, you’ve almost certainly heard about it as an adult through the gestalt of local news (for anyone who’s new to the area, you can learn more about our resident fault here).

But what about the rest of Oakland’s geology?

Keep in mind that geology is a jigsaw puzzle, not a road map. So said Andrew Alden, our geologist guide and author of the very excellent Oakland Geology blog, as we sat almost directly atop the fault at Montclair Playground. We were there to learn about the Cretacous-era geology in the neighborhood, and see some of the 70-80 million year old rock formations that were already ancient by the time mammoths and giant ground sloths got around to munching on Oakland’s prehistoric vegetation.

The three major rock units on our agenda were the Oakland Conglomerate, Shephard Creek Formation, and Redwood Canyon Formation. These three units are all part of the Great Valley Sequence, one of the major rock formations in California; it forms the western wall of the Central Valley and underlies its entire extent.

Oakland Conglomerate. Photo: Andrew Alden

Oakland Conglomerate. Photo: Andrew Alden

Our first stop was the Oakland Conglomerate unit, part of it exposed as a wall of light brown sandstone near an unofficial, hand-made skate park with ramps dug into the hard soil. Andrew mentioned that all sedimentary rock is defined by grain size, not composition of materials, and a “conglomerate” is a geologic term meaning sandstone with pebbles and larger stones in it. This unit was created by sediment from the ocean floor and deposits from mountain rivers, and the larger cobbles are a mix of volcanic and granite rocks. “The Oakland Conglomerate is unusual because it stains red from the iron in it,” he explained. “But no one’s spent much time studying this unit, so we don’t really know a whole lot about it.”

A hundred feet away from where we were standing, the formation changed to the shale of the Shephard Creek Formation, created between 83 and 71 million years ago. Shale is made mostly of clay, which isn’t as strong as the sandstone of the Oakland Conglomerate.

Shephard Creek Formation. Photo: Andrew Alden

Shephard Creek Formation. Photo: Andrew Alden


Our last major unit was the Redwood Canyon Formation, a thick unit of sandstone. This rock, like the other units we saw, was created deep in the Pacific Ocean, where subduction zones and tectonic activity 100 million years ago generated enormous landslides that created thick sandstone beds.

Redwood Canyon Formation. Photo: Andrew Alden

Redwood Canyon Formation. Photo: Andrew Alden


The claystone / turbidite landslide bed are the flaky-looking rocks in the central area of the picture. Photo: Andrew Alden

The claystone / turbidite landslide bed is the band of rectangularly-fractured light gray rock next to the leaf litter. Photo: Andrew Alden

Near the end of the walk we saw a “turbidite” landslide bed of the Shephard Canyon Formation sitting atop flaky claystone consisting only of tiny particles, which give this rock a distinctive look as well as texture. “Go ahead and nibble on a small piece,” advised Andrew, pointing to the claystone. “It breaks up very easily, and it has a creamy feel in your mouth because there’s no grit in its fine sediment.” Who knew that eating rocks could help you identify them?

For a far more in-depth description of the geology of this area, check out Andrew’s blog of this same Wild Oakland walk, titled “Shepherd Canyon: Type localities of Oakland rocks”.

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Identifying the trees of Lake Merritt

By Constance Taylor

If you took a walk around Lake Merritt, how may of the tree species would you be able to identify?

It can be a bit tricky in urban areas because so many of the trees are from different places in the world- you won’t find many Oakland city trees in a “Trees of Western North America” or “Trees of California” guidebook. Most urban California trees are from Asia, Australia, or Europe; in fact, only 6% of commonly planted urban trees are native to California1!

However, there’s a fantastic book called A Californian’s Guide to the Trees Among Us that identifies many of the commonly planted urban trees in the state. It also includes a dichotomous key to help you figure out which species are which so you don’t have to go through the guide page by page to identify a tree you’re standing next to. The funny thing about keys, though, is that they can be notoriously confusing to use. I once heard that keys “are written by people who don’t need them for people who don’t use them”- a joke that usually gets a sympathetic chuckle from anyone who’s ever used a key.

Enter Kristin Tremain, Ivan Parr, and Tammy Lim- Wildlife Society biologists who helped guide us though some key-reading 101! But wait… why would wildlife biologists, who usually deal with studying critters, need to know things about trees? “Trees are nature’s architects,” Kristin explained. “Certain animals- birds and mammals, like to live in certain trees, and to study those animals we have to know where to find them.”

We began with Ivan explaining some basic botanical vocabulary and major features you should look for. For example, is the tree a gymnosperm (conifer), angiosperm (flowering plant), or palm?

Images = Gymnosperm: benjaminreece.com; Angiosperm: internal.champaignschools.org; Palm: idtools.org


Leaves are a really important part of tree identification, so we focused on some of the many words describing very specific attributes of leaves.

Is it a simple leaf or a compound leaf?

Photo: www.uwgb.edu

Photo: www.uwgb.edu


Are the leaves on the branches opposite, alternate, or whorled?

Image: gallery4share.com

Image: gallery4share.com


Are the leaf veins palmate, pinnate, or parallel?

Image: crescentok.com

Image: crescentok.com


Are the edges of the leaf smooth, serrated, lobed, or undulate?

Image: localecologist.org

Image: localecologist.org



Wild Oaklanders identifying trees! Photo: Scott Lindemann / Widlife Society

After the brief indoor tutorial, we went outside and used the key in the Ritter book to help us identify the trees in front of the Rotary Nature Center. Although we focused on trees for this event, these identification basics (and vocabulary) work for any plant.

Here’s a bit of advice from me to you if you’re just starting out with plant ID… don’t be discouraged by the new vocab. It’s important to know the words, but don’t worry if most of them are unfamiliar to you. Even experienced botanists often need the internet or a botanical glossary near them when they’re keying plants! The more you encounter the words, the more familiar they’ll become.

Happy identifying!


1M. Ritter, A Californian’s Guide to the Trees Among Us (Heyday, 2011), xv

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Edible urban weeds- Oakland’s sidewalk salads

By Paul Belz

The gardens at Laney, managed by the Mindful Garden Collective. Photo: Kristen Rasmussen

The Laney edible garden, managed by the Mindful Garden Collective. Photo: Kristen Rasmussen

Part of the message today is that you already have a vegetable garden, whether you planted one or not,” Philip and Kristen told a group of hopeful foragers. “And if you did plant a garden, it’s growing more food than you sowed. Even if you have a burrito in a bag, you can make it more nutritious by adding some wild oxalis.” The participants gathered on a lawn near the Laney edible garden. This garden is managed by the Mindful Garden,collective, which unites Laney College students and local community members who want to grow healthful food.

Philip Stark is Chair of the Department of Statistics at UC Berkeley, and Kristen Rasmussen is Teaching Faculty in the Nutrition and Toxicology Department at UC Berkeley and the Culinary Institute of America. They’re two of the people behind Berkeley Open Source Food (BOSF), an initiative that encourages the use of wild and feral urban plants as a food source. Kristen also created Rooted Food, a blog with lots of delicious ways to eat these weedy volunteers. Dandelion green pesto, anyone?

BOSF maps the availability of edible weeds in “food deserts,” urban areas far from any grocery store, where commercial fresh produce is hard to find. But free produce is easy to find. “It’s become clear that there’s a lot of incredibly tasty and nutritious food going to waste,” Philip said.

Sharing some sow thistle! Photo: Kristen Rasmussen

Sharing some sow thistle! Photo: Kristen Rasmussen

When asked whether the social dignity factor might prevent low-income individuals from being comfortable picking and eating weeds in their neighborhoods, Philip agreed that it was an issue. “That’s why we’re providing education and outreach, including ‘wild food events,’ where top restaurants demonstrate how delicious these plants are. These plants have been part of human diet for thousands of years; they’ve just fallen out of fashion, unfairly marginalized in favor of row crops and industrial agriculture. We are working to remove the stigma, bringing them back into the food system to improve nutrition and gastronomy. All communities certainly need grocery stores that sell fruits and vegetables. But many plants that volunteer in sidewalks and yards can provide an immediate source of delicious, fresh, healthful food for everyone, wherever they live.”

Not only are edible urban weeds nutritious and tasty, they’re also good for the environment. They have practically zero carbon footprint and don’t require watering. They can also be a food source when disaster strikes. “We’re going to have a big earthquake someday, and it would be nice to have some food afterwards,” Philip joked (sort of).

The bounty: vetch, calendula, and plantain. Photo: Kristen Rasmussen

The bounty: vetch, calendula, and plantain. Photo: Kristen Rasmussen

Interestingly, plants like wild mustard, dandelion, and many other “weeds” were intentionally brought from Eurasia as food, but fell out of favor when commercial agriculture started focusing on mass yields and attractive products. “Often we don’t see plants as food unless they’re wrapped in plastic or in a grocery store,” Philip said. He also noted that people often buy plants that they could be gathering—he recalled a visit to a farmer’s market stand selling dandelion greens for $1.75 a bunch, while across the street was an empty lot with bunches of dandelions he could pick for free! “I haven’t bought greens in years,” he remarked.

People might worry about heavy metals like lead or mercury in urban soils, but so far there’s no evidence that common edible weeds accumulate such substances in their tissues. Still, BOSF is currently studying the levels of toxic contaminants in plant tissue. “We’ve been testing the soil in the food desert areas, and the levels of contaminants are below EPA guidelines,” said Philip. While soil contaminant concentrations aren’t high enough to make these plants toxic, foragers should wash the plants before eating them since tire dust and other residues can be harmful.

Current law permits people to forage only from their own property, although an urban gatherer who approaches neighbors politely may find that they are happy to be rid of their weeds. Philip and Kristen hope that future legislation will allow people to pick edible invasive plants from public lands.

Identifying edible plants we found. Photo: Constance Taylor

Identifying edible plants we found. Photo: Constance Taylor

At the end of the day, the group had found 29 species of edible weeds in one urban lot! Philip and Kristen helped the group identify all the plants. These weeds probably grow in the areas where you live; learn to identify them, and eat well!

Additional Resources

Bay Area Open Source Food: Lots of information about edible urban weeds!

Bay Area Baker’s Dozen Wild Edibles: A field guide for beginners created by BOSF

Rooted Food: A foraging and cooking blog by Kristen Rasmussen, with lots of recipes!

Bay Area Forager: A recently published book that has a wealth of information about edible weeds in the Bay Area! It’s available at local bookstores- if they don’t have it on the shelves, they can order it for you. Support independent bookstores and local authors; please don’t buy it from Amazon!

Species list of edible plants found:

Note: Not all parts of these plants are edible! Please do your research before you decide to eat any of them.

– Nasturtium
– Cleaver
– 2 species of sow thistle
– Italian thistle
– Lamb’s quarters
– Yarrow
– 2 species of plantain
– Lavender
– 2 species of wild mustard
– Bristly oxtongue
– Wild radish
– 2 species of mallow
– 2 species of wild lettuce
– Pineapple weed
– Calendula
– Purslane
– Dock
– Dandelion
– Clover
– Vetch
– Filaree
– Sweet fennel
– Cat’s ear
– California poppy

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