Hellhole

The trailhead for Hellhole Canyon in Anza Borrego State Park sports this sign: "People have died on this trail." Well... that seems a little melodramatic... but in summer it certainly could apply, when the temperature can climb to 124º!

Even though today's temperature is a mellow 80º, hikers year-round do need hats and plenty of water on this 5-mile trek. Also Mountain Lions do roam here... and perhaps those of us who live with lions and rattlesnakes grow too accustomed to them, and careless.

Brittlebush (Encelia farinosa) adds sunny splashes to the wildflower display. (All photos by Narca)

Beautiful Desert Hibiscus (Hibiscus denudatus) is in the mallow family.

The trail is fairly level and well-maintained, as it mounts the wide bajada at the foot of Hellhole Canyon. Many flowers are peaking just now, and the wide fan is aflame with the reds of Chuparosa. Shortly after the canyon walls close in, a small stream of water cuts the trail, and in the distance I see a stately grove of California Fan Palm, the only native palm in the southwestern US.

California Fan Palm (Washingtonia filifera) at Hellhole oasis

California Fan Palms grow only at desert oases, where fault lines along the mountains' roots allow water to flow to the surface. Anza Borrego must have gotten a good recent rain, for the flow today is strong, and the sand on the open bajada is still damp below the surface. Ocotillo always flowers after a good, soaking rain, and it is in flower today, and fresher than the Ocotillo was yesterday in Plum Canyon.

Several of the fan palms show scars from a fire, but many have survived. Trunks are scorched, and their long skirts of old fronds are now miniskirts, no longer brushing the ground. I scramble over a boulder with a bedrock mortar, evidence that Native Americans gathered here to grind acorns and other seeds, in the cool shade of the well-watered canyon.

Bedrock mortar at Hellhole Canyon, still holding water from the last rain

California Sycamore (Platanus racemosa) in flower

I'm early, and the sun hasn't yet topped the ridge, so I must wait for its warmth if I'm to see any butterflies. Only a single Mourning Cloak flies before the sun has hit the canyon bottom. A few Orange-crowned and Yellow-rumped Warblers forage in the palms and California Sycamores. Lesser Goldfinches are very conversational this morning, as they gather to drink and bathe.

Male Lesser Goldfinch (Pen-and-ink by Narca)

As soon as the sun hits, the Sara Orangetips fly––dozens of them, the only abundant butterfly today. Variable Checkerspots energetically zoom past, alighting occasionally to bask. On the return trail, only the orangetips and a few blues venture to flowers on the alluvial fan, beyond the water.

Variable Checkerspot (Euphydryas chalcedona hennei)

Like butterflies, lizards emerge with the sun's warmth. Several Side-blotched Lizards scurry away as I return downhill.

A Side-blotched Lizard (Uta stansburiana) has the confidence of a dinosaur, its small size notwithstanding!

One change is very striking: a new plant has invaded the low desert, which I didn't notice on my last visit, and it is already a scourge. The Saharan Mustard. The Arizona-Sonora Desert Museum's website gives a lot of information:

http://www.desertmuseum.org/invaders/invaders_saharamustard.php

This very fast-growing invader is self-pollinated, so every flower sets seed––as many as 16,000 seeds on a single plant! Seeds disperse from broken, tumbling, wind-blown plants. This mustard smothers native plants, and quickly overruns a region with up to 100% coverage. It can form impenetrable stands up to 5 feet high. Then, adding insult, it carries fire into desert communities that don't normally experience fire and can't tolerate it. I probably pull up 100 of the plants growing right along the trail to Hellhole Canyon, but can see many more.

Seed pods of Saharan Mustard (Brassica tournefortii)

Back at the car, Noel has been photographing a pair of Loggerhead Shrikes as they return every couple of minutes to feed their four hatchlings. It is the second shrike nest we've found on this trip. This pair has so far outwitted a pair of Common Ravens that are malingering here, no doubt aware that the shrikes have a nest somewhere nearby. Nestling ravens grow up on a diet that consists largely of the young of other birds. These shrikes are wary of the ravens, though, and, with continuing alert parental care, the four nestlings stand a good chance of surviving. In general, shrike productivity is high. Noel says that a major issue causing declines of Loggerhead Shrikes throughout their range is collision with cars.

Loggerhead Shrike in its dense thicket of a nest shrub

Common Ravens are among the most intelligent of birds.

Shrikes are fascinating birds. Their display is unique: they don't sing complex melodies, or flash brilliant colors to woo a mate. Instead, they build a larder by impaling grasshoppers, lizards, mice and other prey on the thorns of mesquite, the points of agave leaves, or the spikes of barbwire, thus proving to potential mates what good providers they are. (The only Pygmy Mouse that Alan and I have ever seen was one spotted by Arnie Moorhouse in a shrike larder!)

Plum Canyon

We're in Anza Borrego State Park, which showcases the Colorado Desert of southern California. Colorado Desert is basically Sonoran Desert, minus the Saguaro, and with other differences in plant and animal species. It is the Californian expression of Sonoran Desert.

Not far to the north, the habitat grades into Mojave Desert, well-expressed at Joshua Tree National Park. The two deserts, although close to each other, have different rainfall regimes. Mojave Desert is a land primarily of winter rains, while Sonoran Desert receives both winter and summer rains more frequently, and is the lushest of the four North American deserts.

Here at Anza Borrego, Plum Canyon is accessible via a mile-long, primitive road, and a plum of a canyon it is! We've come in search of Sonoran Blues, a very local California butterfly, and one that I've not seen before. Noel is most interested in obtaining photos of the spectacular female, while I just want to see the beast!

Hillside at Plum Canyon (Photos by Narca)

Desert Lavender (Hyptis emoryi) is in the mint family.

We car-camp in Plum Canyon, which is out of the way enough that there is rarely another camper, although it is often visited during the day. The dawn light reveals masses of flowering Chuparosa and Desert Lavender, with California Barrel Cactus and Teddy Bear Cholla cloaking the slopes of the canyon. A short hike upstream brings us to the first Desert Dudleya, the host plant for Sonoran Blue caterpillars.

Desert Dudleya (Dudleya saxosa) adorns the walls of Plum Canyon. 

California Barrel Cactus (Ferrocactus cylindraceous)

Chuperosa or Beloperone (Justicia californica)

We split up in order to cover more ground, a strategy that pretty much guarantees frustration for everyone, as special critters may be seen by one party but missed by the other! And indeed, Noel spots a Western Tailed Blue, which I've never seen, and I find three Bramble Hairstreaks, which he has never seen. But we are both lucky with the grail species, for the Sonoran Blues are flying!

Bramble Hairstreak

Next challenge: yes, they are flying, but are any sitting?

Butterflying requires different strategies and a different nuance of patience from birding. We tramp the canyon for hours and catch numerous glimpses of our quarry. Finally we return to the cars, and just at the trailhead, a male and a female Sonoran Blue discover each other, and with no preliminaries at all, settle down to the serious business of making the next generation of Sonoran Blues.

Amorous Sonoran Blue butterflies

A male Sonoran Blue pauses briefly in his patrol of Plum Canyon.

Forty minutes later, the task has been accomplished, and the male quickly flits away, while the female lingers briefly, working her hind wings vigorously, after the manner of a hairstreak.

A female Sonoran Blue, ready to search out Dudleya to lay her eggs.

Au revoir, little friend!

Our butterflies live in a precarious world, where human activities and changing climate impact their seasonal cycles and their food plants. Even here at Plum Canyon, the last time that Alan, Noel, Jim and I visited, we found that a plant collector had been illegally digging up the Dudleya, the Sonoran Blue's host plant, no doubt for sale to rock gardeners. Noel's favorite side canyon had been ravished by the plant collector––and very recently, for the little holes still remained where the plants had been rooted. This trip, thankfully, we saw no evidence of illegal collecting.

For an outstanding article on the work which Art Shapiro at University of California, Davis, has been doing to correlate climate change with loss of butterfly species, go to this link:
http://www.newsreview.com/sacramento/content?oid=1931830