Category Archives: ahmanson ranch

Painted Lady Butterflies in Upper Las Virgenes Canyon Open Space Preserve

Painted Lady Butterflies in Upper Las Virgenes Canyon Open Space Preserve. May 12, 2019.

Back in March, a profusion of painted lady butterflies in Southern California made headlines. The colorful insects were said to be passing through the area on their way to Oregon and other points to the north.

Two months later millions of the black, orange and white butterflies continue to be seen in the West San Fernando Valley, Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch), and other areas. Recently there has been an uptick in their numbers and there have been some remarkable displays of the flyers along local trails.

Painted lady in Upper Las Virgenes Canyon Open Space Preserve with the characteristic four eyespots on the hindwing.
Painted lady in Upper Las Virgenes Canyon Open Space Preserve with the characteristic four eyespots on the hindwing. Click for a larger image.

There are three very similar species of “lady” butterflies in the genus Vanessa — the painted lady (Vanessa cardui), the American lady (Vanessa virginiensis) and the west coast lady (Vanessa annabella). The Canadian Biodiversity Information Facility web site has a side-by-side comparison of these species and this post on BugGuide.net compares the American lady to the painted lady.

The lady butterflies I’ve looked at closely in Upper Las Virgenes Canyon Open Space Preserve have the identifying characteristics of the painted lady (Vanessa cardui). Here are an open-wing photo and a closed-wing photo of painted lady butterflies in Upper Las Virgenes Canyon Open Space Preserve.

This three-minute slow-motion video of painted lady butterflies in upper Las Virgenes Canyon reveals their fluid, bird-like flight. The purple flowers in the video are winter vetch, an introduced plant which is also more abundant this year.

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Guardian Oaks

Young valley oaks and coast live oaks at the edge of the canopy of large valley oak in Upper Las Virgenes Canyon Open Space Preserve.

One day while running at Ahmanson Ranch, I was admiring the stately limbs of a large valley oak, and noticed that along the margin of the canopy were several sapling oaks. As I continued my run, I found that only a few other valley oaks hosted a brood of young trees.

That oaks would sprout on the margin of the canopy made sense. There is an abundance of acorns at the ends of the limbs. It is also where water drips from the oak’s leaves on foggy days or when there is light rain or drizzle. The mix of sun and shade on the edge of the canopy is the perfect place for a young oak to thrive.

The surprise came when I took a closer look at the young trees. Most were valley oaks — the same as the shepherding tree — but in some cases the young trees were coast live oaks! And sometimes there was no obvious parent coast live oak nearby.

Of course, there are plenty of coast live oaks at Ahmanson and several ways for their acorns to find their way under a valley oak. Birds and squirrels love to stash acorns, and gravity is good at moving round things downhill.

Time is at a different scale for a tree. In my mind’s eye I accelerated time and watched as the young oaks surrounding a guardian oak grew in stature. Fire sweeps through the frame on several occasions. During one fire the old brood tree collapses and in another fire, the collapsed tree disappears from the frame. Of the young oaks that have survived, one dominates, spreading its limbs and growing large and robust. Along the margins of its canopy, I can see several sapling oaks…

Note: The young oaks in the title photo are an older brood that survived the Woolsey Fire, but many younger sapling oaks were killed. Introduced grasses, black mustard, and other introduced plants produce higher fuel loads than native equivalents and increase fire mortality.

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Chinese Houses Along the Sheep Corral Trail

Chinese Houses (Collinsia heterophylla) along the Sheep Corral Trail

Wildflowers continue to flourish following our wet rain season. Above average precipitation tends to produce more wildflowers, a wider variety of wildflowers, larger patches of a wildflower species, larger plants, and in some cases larger blossoms.

During the week I photographed several new “Weekday Wildflowers” on runs from the Victory Trailhead of Upper Las Virgenes Canyon Open Space Preserve. This week’s runs included Lasky Mesa, Upper Las Virgenes Canyon, and the Sheep Corral Trail.

Chinese houses, white snapdragon, yellow monkey flower, stinging lupine, and a few other species were added to the Weekday Wildflowers slideshow.

Related post: Weekday Wildflowers

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