SF Natural History Series

Bruce Rogers, a geologist and cave explorer from since he was a teen, came to us in September of 2015 to talk to us about caves. This was our last talk at the Exploratorium this year. The talk got off to a rocky start with not one but two fire alarms going off! We only had to evacuate once, but we were impressed by how many people (easily 90%) stuck it out.

Bruce starting with a definition of caves as underground, naturally occurring, with some parts in darkness, and humanly accessible. They have fascinated humans since probably long before we were even “human” (if the recent cave findings in South Africa have any bearing). For us they represent beauty, danger, and adventure, where of course for a long time they were likely refuges and homes.

Beyond that, to science and wider human interest they are even more interesting — they are geological repositories, they are workshops of evolution, they are archaeological sites, and holders of cultural treasures.

California has a few different types of caves across its landscape: limestone/marble caves, tafoni wind caves (tafoni is an italian word for small grottos built overlooking the ocean), sea caves, and fissure caves.

The ecology of caves can often be novel and fascinating, with new species often being described when new caves are found. Microbiology provides another level of this — with astrobiologists of late showing great interest in finding how life can live on in places like this, and where we might expect to find things alive on places like Mars.

There are creatures like the California giant salamander, one of the few salamanders to make noise. And of course bats — which Bruce in his cave explorations is careful not to disturb.

One cave near Monterey bay contained a graveyard of skunks, the skeletons of several thousand were found there in 1942. The skunks no longer seem to come back, but there are bats still in the cave. Mountain lions make use of caves in Big Basin.

Of course, all these caves are fragile, and their conservation is always a concern. He showed one example of cave that was discovered in 1954 (through an accident where someone got stuck, it soon became widely known) by 2007 everything had been broken off, the floors sledgehammered, full of garbage, and walls of graffiti. Spelunkers are now pretty wary of telling people of their finds, and recent caves opened to the public go to great lengths to preserve them from the outside. Caves do not renew — or at least not on any timescale we live on.

Sea caves are by far the most common type of cave in the Bay Area, created by the impact of waves along the bases of cliffs. Waves bring a tremendous amount of force to bear on cliffs. During hurricanes it can be enough to bend steel and smash concrete — but even a normal wave brings a lot more pressure to bear than most human activity.

Sea caves can be full of life, fish, seaweed, snails, limpets, anemones, mussels, barnacles, abalone, sea stars, sea lions (seals apparently don’t like caves). They can also be full of sand — the season, tide, and wave action can completely change a cave (he showed one picture of a cave with people standing upright in, and the next was someone crawling through the sand).

If you have an inclination to visit one — be wary! Be careful about the tide, and only go at extremely low tides.

There may be things to discover as well — At least there was… in 1927, a couple recovered some stolen silver in one of the sea caves. A stash of stolen goods from Hotels through San Francisco.

The Farallones also have some caves, quite large ones, with endemic species of a cave cricket and a salamander, and some very uncommon stalactites, and beautiful flowstone.

The only fissure cave he talked about is now on private land. There are not many limestone caves in the region either. The other most common cave type you will find in the Bay Area are tafoni caves — Castle Rock State Park have good examples, as well as Mt Diablo, and the Vasco Caves. The Vasco caves are part of a closed preserve: they have some 2000-4000 year old cave paintings and rare wildlife and plant species. You can get naturalist led tours of it in Spring and Fall.

If you want to know more about caves, preserving and exploring them, Bruce pointed us towards http://caves.org/

Kieth Hansen joined us April 29th, 2015 at Green Apple Books. The first of our series’ “wandering era.”

Kieth Hansen has been hooked on birds since he was a kid, when his brother ran into to grab him, and showed him a Cedar Waxwing in the woods of Maryland. Not long after, his family moved to Fresno, where the Sierra Nevada became his backyard, and he went deep into birding, and on to do a 3 week stint on the Farallones with PRBO in 1974 as the youngest person to be allowed on the islands. Since then his birding has taken him all over the world.

He also came from an artistic family, and those two interests were have been tied together since his senior year of high school. His first book was a coloring book about birds of the Sierra, followed by a 4 year project to produce illustrations for “Discovering Sierra Birds” co-authored by my Ted Beedy and Steve Granholm.

His most recent project has been one 14 years in the making — 1400 paintings of 320 species each with their different plumages based on sex, age, seasonality — called “Birds of the Sierra Nevada: Their Natural History, Status and Distribution” with co-authors Ted Beedy and Ed Pandolfino.”

Originally it was planned as one book, but the field guide + life history became too much. The life history book has been published first with example images from the field guide illustrations.

To paint one illustration takes about 2 months from a blank canvas, a slow process of building up the picture of the bird, starting with pencil, measuring out and couting the feathers; wetting the bird and starting with a neutral tint for shadow, then adding color, sheer washes over each other, drawing more while the paint drys, then back to paint; paying attention to the translucency of feathers as they overlap; the full colored bird building up slowly but surely; the final touches in place with colored pencil.

A lot of these images are made up, not directly from a photo or illustration, but trying to get the bird in the perfect pose: pulling from his own years of observation, videos he has taken, specimens, other books, and photos. Consulting with his many birding friends and experts in the birding world to make sure he has gotten it right. This is his 13th book, and for the most part he can block birds out without too much work, it’s the details that take the time and effort. Although he enjoys it, he does not draw as much as he would like in the field.

His love of birds is clear from the beauty of his final exquisite images, and he takes inspiration from his trips out in the field (he showed a great video of birds in the Sierra’s) and also in his backyard in Bolinas. His studio has proved itself an excellent little observatory as well.

His images are fairly small — but this is mostly a factor that he has had to draw so many, and that they will actually be even smaller in the book. He has been pleased to see how well they can be blown up though. One of the most important factors in getting the birds right is their weight and center of gravity — how they carry themselves, and their relation of their legs to the body.

We still illustrate bird guides he says, because they can be drawn in a neutral space, the same generic conditions and lighting to make them easier to compare, and it is easier to highlight and show features. A photo guide has the disadvantage of having a background and the varied lighting, and varied conditions. With an illustration it is easier to show the details and variations that matter.

I hope that he keeps illustrating birds for many years to come. His studio in downtown Bolinas is well worth a visit (he related a funny story about why he has so many hummingbird feeders). He also leads tours through a company called Sacred Monkey. More information can be found on his website at http://keithhansen.com/