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Art California Natives - Fauna California Natives - Flora Nature Photography

Painted Lady (Vanessa cardui)

Vanessa cardui is having a big numbers year. Millions, perhaps billions of butterflies are migrating in multi-generational waves from the southern desert areas in Mexico and California northward as far as the Pacific Northwest.

The Painted Lady’s migratory cycle occurs each year. This year, because of a high volume of winter rain and plant growth in the western desert and in much of California, the migration continues to be remarkable with what appears to be multiples waves of butterflies.

The cycle begins with an overwintering population of adult butterflies in the desert. They wait for rain, mate, then the females lay eggs on sprouting host plants before they die. Lots of rain means more host plants, nectar plants and butterflies.

The heavy rains last winter nourished so much plant growth in the desert and along the butterfly’s migratory path that we have been hearing about, referring to and witnessing the wildflower superbloom since January. The butterflies are in a coinciding population boom. Abundant sustenance for the hatching larvae has made it possible for a countless number of them to develop into adults at different points along the migratory route.

As the butterflies pass through Ventura and Los Angeles counties, females nearing the end of their fat stores and lifespan mate and lay eggs on suitable plants in the mountains and open space. On recent hikes I have seen the Painted Lady caterpillars on several species of thistles, lupines and phacelia. All three are members of plant families that the caterpillars will eat. (The Painted Lady is a generalist when it comes to host plants. Some butterflies are much more specific. For example, the Monarch larvae will eat only milkweed.)

The next generation continues the migration northward until it reaches a northern destination. How does a migrating butterfly species know when to stop flying in a particular direction? Experts in the field are still conducting research to answer this question, so I will use a broad brush to venture my answer:  Evolution. Millennia of practice, trial and error and natural selection for attributes that support the survival of a species.

In late summer, a future generation will begin the return trip southward, back to the southern points in the desert. In winter, the cycle begins again.

For more information about one of the most powerful and adaptive creatures in the world of Lepidoptera, visit Dr. Art Shapiro’s Vanessa cardui page. Dr. Shapiro is a professor of ecology and evolution at UC Davis. He has been studying butterfly population “trends” and migration for 34 years based upon data collected at specific monitoring sites in Central California.

 

Categories
California Natives - Fauna California Natives - Flora Nature Photography

Blainville’s Horned Lizard on the Meadow Vista Trail

Last Saturday my sister Roxanne and I hiked a loop on trails in the Lang Ranch and Woodridge open space. As has become my habit, I took photos of wildflowers. While walking down the Meadow Vista trail, my sister heard a rustling sound and turned to spot an unusual creature trying to hide in a sparse section of branches and grass along the inner side of the trail. The maker of the rustling sound turned out to be a horned lizard.

While a couple other species of horned lizards are native to California, their ranges do not appear to overlap. What my sister spotted was a Blainville’s or Coast Horned Lizard (Phrynosoma blainvillii). In this case, aside from range information, identification is all about the lizard’s fringe scales, the number of rows and how pointed they are.

The lizard was attempting to get away from us, of course, by climbing a steep embankment which it succeeded in scaling after a few tries, but not before I took some photos. Now that is camouflage!

The primary food source of the Blainville’s Horned Lizard is the native Harvester ant, supplemented by other insects. Both of these species have evolved to live in an arid Mediterranean climate such as the one we enjoy in coastal southern California.

The decline of the Harvester ant population is due in part to the successful invasion (circa 1907 in California) and continued expansion of the non-native Argentine ant into the Harvester’s habitat. The two ant species are very different but the details of their differences are for a future post. The broad bush takeaway is that the Harvester’s presence contributes to and supports the ecosystem we rely on while the Argentine weakens it. (The Argentine ant is also the one that invades your house at certain times of the year.)

The Harvester’s decline is one of the causes of the Blainville’s Horned Lizard own decline in its range. Habitat loss due to agriculture and development has also contributed to a drop in numbers across the lizard’s range.

The California Department of Fish and Wildlife lists the Blainville’s Horned Lizard as a California Species of Special Concern.

Photo of lizard trying to scale an embankment.
Having noticed possible predators (two hikers), this lizard breaks his still pose and tries to run up the side of a trail embankment.
Photo of the lizard remaining alert after scaling an embankment to escape the proximity of two curious hikers.
The lizard remains alert after scaling an embankment to escape the proximity of two curious hikers.

Photo of a Blainville's Horned Lizard relying upon camouflage to blend in with its surroundings.
A Blainville’s Horned Lizard relies upon camouflage to blend in with its surroundings.
Categories
California Natives - Fauna California Natives - Flora Nature Photography

White-lined Sphinx Moth

On a recent hike with a friend, Silvia, we came across a late instar of a White-lined Sphinx (Hyles lineata) caterpillar that was probably looking for another plant to consume followed by a good place to pupate. Silvia nick-named him Gilberto.

The color and markings of this moth’s larvae varies. All the individuals I have seen in the area are black with yellow stripes and orange spots but the larvae can also be green with other markings such as red or orange spots encircled by black. A harmless horn at the back end is always present in this species regardless of coloration.

This video shows our brief encounter with Gilberto and includes some basic information about the White-lined Sphinx moth. Cyclists, hikers and runners in our area (Los Angeles and Ventura counties) have seen (and continue to see) lots of the caterpillars this spring.

A few days after our hike I was bicycling in the Santa Monica Mountains. I stopped to photograph flowers along the side of Decker Canyon road and noticed a White-lined Sphinx larva trying to climb up and repeatedly rolling back down a steep “hill” of loose dirt. I gave it a lift onto a “ledge” among a clump of Parry’s Phacelia before continuing on my ride.

(Parry’s is in a prolific phase of bloom in the mountains right now. Like poppies? Take a look at, but do not tread on, the phacelia.)

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California Natives - Flora Nature Photography Uncategorized

Conejo Open Space: Autumn Ridge and Sunrise Trails

In Thousand Oaks we are fortunate to live near relatively wild land with more than 150 miles of trails. I like to hike and trail run; more recently I am learning to mountain bike on some of the trails protected by the Conejo Open Space Conservation Agency (COSTAC).

The Conejo Open Space “…offers a safe, stable environment for all organisms, whose complex interactions combine to form valuable habitat and ecosystems.” COSTAC’s Mission is “To acquire, conserve, and manage open space within and surrounding the Conejo Valley for future generations, sustainably balancing public use with ecosystem protection.”

The Conejo Open Space Foundation (COSF) is a not-for-profit organization staffed by volunteers, members of the public who donate their time and expertise by participating in a variety of programs focused on promoting the use of and protecting/maintaining the health of our open space resources. Education, trail watch/monitoring and fundraising are just a few of the ways that the public can get involved. If you are already spending time in the open space, probably the easiest way to get involved is as a trail watch volunteer.

COSF is currently holding the Conejo Open Space Challenge through the end of May that encourages hikers, cyclists, equestrians and runner to explore each of ten trails located with the open space and share photos of each outing via Twitter, Instagram or email. The challenge is not a competition, but participants may enter a raffle to be eligible for donor prizes if they complete all ten trails. And there’s going to be a party!

I took some of the photos in the featured slideshow while on the Autumn Ridge trail. Autumn Ridge is one of the ten Challenge hikes. I recommend a return along the Sunrise trail because each trail has its own set of unique wildflowers although there is some overlap.

After the Woolsey fire, we are still not sure how much has been lost, or how long it may take for nature to repair the damage. Some damage may be permanent, but the resilience of the wildflowers, shrubs and mighty oaks trees coming back is inspiring.