Butterflies

Thinking About Weeds and Wildflowers

Micro-Habitats; Knowing Your Land

My husband and I live on a south facing hillside situated above the Novato Creek floodplains; it’s a beautiful, warm, and sunny spot with a great vantage point. Our hill, called Cherry Hill on some maps, is a part of one of the ridges extending from Mt. Burdell, the 3rd highest peak in Marin County, and we’re directly facing Big Rock Ridge, the 2nd highest spot in Marin. When the skies are clear, we can actually see just a little tip of Mt. Tamalpais, the highest peak in Marin! To the east, we can see the twin peaks of Mt. Diablo, which is the highest peak of all in our area and therefore the base meridian of much of northern California.

The views are wonderful here on our land, but the rainfall is sometimes disappointing; while other places in Marin are measuring and inch or so, we might get ¼ of an inch of rain! We’re in a rain shadow; I can see all the rain falling on the north side of Big Rock Ridge and in Indian Valley, but the clouds are often blown east. If they do get to our side, there’s not much moisture left. 

Even so, with not much more than an inch of rain, I’m witnessing an almost instantaneous re-greening of the landscape! Within days thousands of seeds are germinating; lots of grasses, and a great variety of weeds and wildflowers. This is where the fun begins. I love the challenge of identifying these minute plantlets. Sometimes I’m already so familiar with the plant that I know it from the cotyledons, but very often I need to see the first true leaves before I really know what they are.

Thinking About Weeds

Annual grass seeds are amongst the first to germinate, and of course wild oats (Avena species) are well represented. Wild oats, very different looking than the native Oatgrass (Danthonia californica) were introduced from Europe and brought to California, most likely with the very first Spanish settlers who brought livestock, and with them the seeds of these grasses. In Europe, during the olden times, the leafy new spring growth of one wild oat species (Avena sativa) was used as a medicinal to treat various conditions, including diminished sex drive. This is where the term "sowing one’s wild oats" originates from!

Along with the annual grasses come lots of thistle seedlings; their cotyledons are large and somewhat spoon-shaped. I can identify Italian thistles (Carduus pycnocephalus) easily when the first set of small and somewhat spiky, medium-green true leaves have developed. Some of the non-native weeds, including thistles, that plague wild areas in Marin, are thought to have been brought to the county by Samuel P. Taylor in raw materials for his paper mill. At first there was plenty of wood pulp locally available, but as those sources dwindled, and while the demand for paper kept going up, he also made paper using rags that were imported from Europe. It’s within these supplies that the seeds of some European weeds are thought to have "hitched a ride".

Here’s where my thoughts about weeds differ from those of many others; weeds are not all bad! 

Weedy Habitat

The Flickers have now left my oak woodlands and moved to higher elevations in the Coast Ranges; I’ll look forward to seeing them again when we’re camping in the forests this summer. Meanwhile, the Tree Swallows are here already and I’m waiting to hear the first calls of the Ash-throated Flycatchers as they arrive from wintering grounds in Baja California. For the last five or six years they have shown up about the fifth of May, and by June are raising a brood in the nesting box hung in an old Coast Live Oak.

More on Lycaenidae

Several other smaller groups of butterflies are included in the larger family commonly known as the Gossamer-winged butterflies; there are the Blues, the Coppers, Metalmarks and Hairstreaks. Most of these small butterflies are uncommon in Marin gardens; many of them have associations with just one or two species of native plants in specific habitats. There is just one butterfly within the sub-family of Hairstreaks that is often seen in Marin gardens, and that’s the Common, or Gray Hairstreak.

Acmon Blues

Acmon Blue – Plebejus (Icaricia) acmon

This little butterfly is fairly common, and more widespread than some of the other ‘Gossamer Wings’ (Lycaenidae); the Acmon Blue has a much longer flight period than many other ‘blues’ and it visits gardens, and can be seen in open fields, and even along roadsides.

On Gossamer Wings

The Lycaenidae; Blues, Hairstreaks, Coppers, and Metalmarks, are usually small, very delicate looking butterflies; many of them brilliantly colored and some with very interesting life cycles. The apparent fragility of these tiny creatures earned the family the common name ‘gossamer-winged’; but the vigor apparent in their life strategies, belies this moniker. This is the largest family of butterflies, with almost 6,000 species worldwide; but named species are often termed ‘complexes’ because there is still so much to be learned about their anatomy and behaviors.

Cabbage White

This lovely little Cabbage White butterfly (Pieris rapae) really stands out against the beautiful flowers of the 'Santa Cruz' Oregano.  It might seem unsafe, for a small creature, to be so visible in a habitat garden full of other creatures; but the white color sends a warning to visual predators.

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