Up and Down Flag Hill

I packed everything the night before and woke the wife and kids early. A quick bowl of cereal and a cup of tea and we were off in the car to 6,000-acre Sunol Regional Wilderness, one of our favorite hiking spots in the San Francisco Bay Area. We arrived not long after 8am when the rangers opened the access gate. From the small parking lot we crossed a footbridge and passed briefly alongside Alameda Creek before turning up the trail to Flag Hill. I took a single photograph, discovered that my battery was depleted, and then traded the camera for the binoculars which I used the rest of the day.

Halfway to the summit, we stopped to admire several white-breasted nuthatches among the oaks. They blithely ignored us but made their rounds from trunk to trunk, ascending and descending like angels on a Jacob’s ladder, even hanging upside down to stab at insects. Farther up Flag Hill, above a band of fossil-bearing sandstone that once was part of an ocean floor, the oaks fell away. Looking out from the sage scrub and chaparral we saw yellow-billed magpies solitarily stalking the dry grassy slopes or bobbing up from the treetops in pairs (tending their nests, to judge by the sounds of young).

The yellow-billed magpie is perfectly like its black-billed cousin with the single exception of its bill color, and so there’s some debate whether these in fact constitute separate species. Their ranges, however, do not overlap and the yellow-billed is found only in California’s mid-section. They carry different Latin names too: Pica hudsonia for the black-billed and Pica nutalli for the yellow, the latter so christened to honor the long-time expatriate British naturalist Thomas Nuttall. Readers of footnotes will learn that Mr. Nuttall makes a brief, unnamed appearance in the San Diego section of Richard Henry Dana’s Two Years Before the Mast.

At the rocky top of Flag Hill (1,360 ft.) we took in the view southward down the rift of the Calaveras Fault. With a little education, the vista reveals itself as a scene of tremendous geological violence. Today the Calaveras – like the San Andreas, of which it is a tributary – is a transform fault where two plates grind slowly past one another. In the ancient past this was a subduction zone fault, where one plate slid over the top of another. This made for significant upheavals and the Coast Ranges here are a tectonic mélange of young seabed sandstone and an older brew of serpentine schist, basalt, greenstone and chert.

Descending the far side of Flag Hill we saw, briefly, a probable Bullock’s oriole – a flashing dart of bright orange, yellow and black – here in its breeding grounds. We saw more magpies too, and the regulars: California towhees, black-eyed juncos, Anna’s hummingbirds, crows, vultures, scrub and Steller’s jays, etc. We stopped for an early lunch at High Meadow Camp where an older gentleman, tall and thin, came up the trail with his little long-haired dachshund. How her tiny legs had brought her so far, we couldn’t understand. She was his regular hiking companion, he said, but she typically pooped out after the second mile of the day. Presumably he carried her after that.

We compared notes over lunch, talking rattlesnakes, mountain lions and birds, among other things. He showed us a yard-long piece of still-green wild grass that he’d picked. At the top of it he’d made a small lasso by tying it back round itself in a loop. This, he said, he’d learned to do as a boy. It was a tool for catching lizards. All that was needed was to slowly place the loop over the head of the creature. With yourself several feet away and nothing very objectionable in a piece of grass, the oblivious fence lizards fell for it every time. Passing down the trail back to the parking lot we made one of these ourselves. But the morning clouds had only just scattered, the sun was weak, and it was still too early for lizards.


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