Doug's Mountain Journal
A Chronicle of Natural History on San Bruno Mountain

Doug Allshouse has been writing his seasonal Mountain Journal for many years. It appears in the quarterly newsletters of the Yerba Buena Chapter of the California Native Plant Society (CNPS). We are very pleased to share his reflections on the natural history of the Mountain. Together with David Nelson, he is writing The Natural History of the San Bruno Mountains. The book will be published by Heyday Books.

Bust out the dancing shoes because we’ve got serious work to do. Strike up the rhythmic beat of those drums, BOOM-bum-bum-bum-BOOM-bum-bum-bum. Is it raining yet? The best laid plans or dances might not shake us out of a disappointing winter rain season. Last year at this time we had 21.35 inches of precipitation. This year November was good at 3.12, but December pooped out with 0.06 and January was promising with 5.23 for 9.68 inches so far but 11.67 inches short of last year. At least it’s been cold for the most part except for the warm spell in February.

I had a pair of ravens following me around the Saddle Trail one mid-January morning. I was on the northeast portion of the trail heading toward home and one raven landed on the road behind me and the other on the road ahead of me. Suddenly, I saw what looked like a hawk streaking madly toward us at a low altitude. Turned out to be a female Northern Harrier who was a bit hot and bothered by 2 ravens in her territory. They scattered right away, but what an exhilarating experience; made my morning as she patrolled her territory.

I never have written about a tiny creature that is, frankly, quite interesting. So, you’re walking on a trail that is littered with leaves; could be San Bruno Mountain or Mount Davidson or Mount Sutro. You stop and look down, take your foot and scrape away the leaves exposing the ground beneath. Stirring up the leaves uncovers these small 5-8 mm long “bugs” which are actually crustaceans, causing them to scurry about or jump like fleas. Trying to catch one is a lesson in humility. You, my friend, have just introduced yourself to Lawn Shrimp. You’ve read me right, lawn shrimp; tiny amphipods in the Talitridae family, the beach hoppers. Arcitalitrus sylvaticus live within the top 1-2 cm of soil and are most often encountered on eucalyptus leaf-covered trails moistened with fog drip or rain.

Lawn Shrimp - Arcitalitrus sylvaticus — Lawn Shrimp - *Arcitalitrus sylvaticus*

They are compressed laterally which gives them a shrimp-like appearance and are brownish-black when alive, turning red when they die; much like crabs or lobsters do when cooked. They constantly seek wetter or drier locations because these amphipods require a slightly damp humidity. The absence of a waterproof waxy layer prohibits control of internal moisture. If it’s too dry they desiccate and die; too wet, they drown. There are 2 pairs of antennae, one long and one very small. These scavengers have chewing mouth parts and seven thoracic segments with leg-like appendages. The abdominal segments are fused so the thoracic segments make up most of the body. They eat dead organic matter, favoring eucalyptus leaves since they are also native to Australia. Eggs are deposited in a brood pouch on the underside of the female and hatch in one 1-3 weeks. The young leave the pouch in 1-8 days when the female has her molt during mating. It takes about a year to complete the life cycle from egg to adult. Lawn shrimp are in the same family as “beach fleas” that live under piles of seaweed and other drift material. They are often confused with springtails, which are insects. The specific epithet sylvaticus means of or belonging to the woods. They were first observed in San Francisco in 1967.

January 8-9 brought us the first good storm system so far. It dumped 3.65 inches in my rain gauge a block north of the park. It rained almost constantly for two days and when I checked the effects of the rain I was surprised that a few drainage ditches on the Old Guadalupe Trail had standing water and Colma Creek was running much higher than usual under both bridges in the bog. Usually this doesn’t happen until well over 10 inches of rain falls. I surmised that because the last two rain seasons had brought over 5 feet of precipitation that the water table in this area was still very high. A few weeks later, meteorologist Spencer Christian of ABC7 News brought up that very item. If we can squeeze 10-12 more inches of rain the next couple of months, we will approach normality.

I’m always fascinated with plants that bloom outside their expected period. The non-native Himalayan blackberry is especially guilty of this, but on the Day Camp Road there are two cow parsnips that were in full bloom in late December and are now in full fruit. Most of the cow parsnip is showing the first leaves bolting out of the ground, as they should in February, but these two are ahead of the game. Its genus Heracleum is named for Hercules and everything about this plant is BIG, as in maximum, its specific epithet. The mature seeds feed nesting birds. Virtually every Native nation used the plant as a green vegetable before flowering. The name Indian celery came from the stem, which was peeled and eaten raw and was sweet, despite the strong odor of the leaves and outer skin. A poultice was used to treat bruises and sores. This is the best plant to illustrate its inflorescence, the compound umbel.

The manzanitas are starting to bloom, and I’ve seen some other parsnips (Lomatium) sending up bright yellow umbels. Checkerbloom has broken ground as well as some lupines. I’ve seen a few western dog violets, seaside daisy, Franciscan wallflower, and footsteps-of-spring. Our favorite time of the year is here, and while the confines of San Francisco offer some good wildflower viewing, spend a nice late winter or early spring day on San Bruno Mountain.

The only problem is that there are so many good places to visit. The Saddle or Summit Trails are easily accessible from the main parking lots. Get into Brisbane and walk up the Quarry Road Trail at San Francisco Street and visit Buckeye and Owl Canyons for oak and bay riparian forests and grasslands for a totally different feeling and plant palette. It’s starting to happen now.

See you on the Mountain,

Doug