Tuesday, November 29, 2011

Pit Pond

A few miles south of Lake Pleasant, on a patch of land where burros eek out a living in Peoria, Arizona, there is a huge rectangular pond. You won't see it on most maps, but it does show up on Google Earth. The lake is a recent addition to the landscape,  a wetland created by filling in a giant gravel pit. In the evenings, thousands of water birds congregate there: coots, ducks, geese, herons, egrets and the occasional swan. We caught the sunset from the cattail-rimmed shore last week, and a flock of ducks on the wing.

Whenever I find these places in the otherwise ultra-arid Sonoran desert, 
I am reminded that life loves heat. You just have to add water!

Monday, November 28, 2011

Burro Crimes

On a thin scrap of wild desert bounded on three sides by roads and one side by a 80-foot wide canal, this herd of about a dozen burros make a living eating the meager foliage that sprouts up among the saguaros and palo verde. I go out and visit this herd every few months, finding them by following fresh tracks and muffins they've left behind. They are curious, but cautious, always stopping to watch me, ears perked up, intent. But as soon as I move toward them, they trot away and then stop at a prescribed safe distance of about 500 feet to watch me again.

Since 1971, with the passage of the Wild Free-roaming Horses and Burros Act, burros have been managed according to AML's or "appropriate management levels" determined by wildlife biologists and resource management specialists. Whereas this used to mean rounding up animals and shooting them, today they are auctioned off as pets.

This small herd is part of the Lake Pleasant management unit, where a population of around 350-400 burros roam freely. Without management, burro populations grow rapidly, and burro crimes ensue. Impacts to springs and riparian areas, competition with native wildlife, altering archaeological and cultural resources, damage to vegetation and soil erosion from trampling are the most frequent citations given to wild burros.

As I gaze across the desert at the power lines spidering out from one of the regions largest electric plants just north of this burro refuge, and watch dust spiraling up from the dirt bike park on the other side of the canal, I often wonder: What would the AML of modern humans be, if our populations were assessed for our damages as burros' are? And who would adopt us?

Tuesday, November 22, 2011

Castor Bean

Castor bean (Ricinus communis) is a spectacular plant native to tropical regions of the Eastern hemisphere. Growing up to fifteen feet high with leaves the size of large pizzas (16" diameter), walking through a patch of castor bean plants truly feels like being in a jungle. We found them thriving in South Phoenix at the Tres Rios Wetland Preserve, where effluent from a sewage treatment plant is being used to restore wildlife habitat near the confluence of the Salt, Agua Fria and Gila Rivers. Conversely, the wetlands serve as a natural purification treatment for wastewater before it returns to the river system.

Castor, which is not really a bean, but a member of the Spurge Family (Euphorbiaceae), is well-known for its use in folk medicine, primarily as a powerful laxative. However, the seeds, from which the oil is derived, are also highly toxic. The main toxic element, ricin, is reputed to have been used in espionage and torture. Ingestion of a handful of seeds can result in painful death. This does not seem to deter horticulturists who still cultivate many hybrids of the species for use as ornamentals. Wild castor bean in the Phoenix area are escapees from urban gardens, where the lush growth is welcome in our sometimes austere desert environment.

Orion in front of a field of castor bean plants at Tres Rios Wetlands

Sunday, November 20, 2011


This Western Screech Owl (Otus kennecottii) was one of dozens of raptors on display at the Adobe Mountain Wildlife Center open house this weekend. Anyone venturing into Phoenix from the north on I-17 zooms past Adobe Mountain, which is west of the freeway just south of Happy Valley Road. Critters in the care of dozens of dedicated volunteers range from bats to bobcats, rattlesnakes and woodrats, tortoises and turkey vultures.

In this photo, the owl is posed in a cavity carved into a section of ponderosa pine, but down in these parts, they are more likely to be found in saguaros. Like many other owl species, the screech adapts well to suburban habitats, where irrigated lawns, golf course, gardens and ball fields provide excellent forage for their favorite prey: mice, rabbits, small birds and insects. Since they are primarily nocturnal, they are rarely noticed by humans. This was the first screech owl I have seen in my lifetime. Sadly, the second one I saw was later that day on my way home, when I found one dead in the middle of the road, where it had been hit by a car as it dove for prey. More fortunate animals may recover from non-lethal injuries if brought to Adobe Mountain. Some become part of the education team, or if lucky, are released back into the wild.

Saturday, November 19, 2011

Cotton Pickin'

On the perimeter of Phoenix, you can still find fields of cotton, one of the "5 C's" that were the foundation of Arizona's economy one hundred years ago. (Do you know the other four? See my post on November 3rd, 2009 for the answer!) Today we cruised by some acreage with both flowers and ripe bolls bursting with downy white fibers. Mexican cotton (Gossypium hirsutum) is the primary species being cultivated in the cotton industry today around the world, and is native to the Sonoran desert. Although many cotton farms have been converted to suburban housing over the past few decades, the industry still contributes over $250 million dollars to the state's economy, according to the National Cotton Council of America.

Friday, November 18, 2011


The view out my bedroom window is dominated by a jojoba shrub (Simmondsia chinensis), which is just beginning to burst into bloom. Jojoba is dioecious, which means there are "male," or pollen producing plants and "female" or seed-producing plants. The flowers in the photo above are males. Fortunately, I've got one of each in my backyard, so in a good year, we get some jojoba nuts, which are edible, although not so tasty as to inspire use as an ingredient in snack bars.

However, chances are high that you have a bit of jojoba in your household, since the waxy oil in the nuts has been harvested from commercial plantations of jojoba since the 1970's as an ingredient for cosmetics, pharmaceuticals, and industrial lubricants. The oil is famous for being a replacement for sperm whale oil, which was historically preferred for certain industrial applications because of its excellent heat tolerance and resistance to oxidation. The importation of sperm whale oil to the U.S. was banned in 1971.

Jojoba is an ultra drought tolerant native to the Sonoran desert, but is now cultivated all over the world in arid regions both as an ornamental landscaping plant as well as a commercial crop.

Thursday, November 17, 2011

Tortoise Bones

Last week we found this scute, a section of shell from a Sonoran desert tortoise (Gopherus morafkai), lying at the edge of a trail we were biking on. Recognizing that it had to have been attached to a rather large tortoise, we explored the area and within minutes found the still smelly, decaying remains of an ancient male. Measuring 12” long and 8” wide (30cm x 20cm), this guy must have been in the upper end of the 80-100 year life span. The crack in his shell tells another story, perhaps a fatal tumble down the rocky hillside where he once roamed. A dozen more scutes were scattered about, although many are missing after three separate visits to look for the old one’s burrow, which we also haven’t found.

This is the second tortoise shell I’ve found in the Deem Hills, a desert island that backs up to the neighborhood we live in. The home of this desert tortoise is just a few blocks from my own; both are visible in this photo. Next time I cross paths with a wild tortoise, I hope that it’s a live one!

Through analysis of DNA and other characteristics, tortoises that live east and south of the Colorado River were recently distinguished from the Mojave desert tortoise (Gopherus agassizii) as a new species. Read more in this June 2011 scientific publication on tortoise taxonomy.

Wednesday, November 16, 2011

Signs of Spring

About half an inch of rain has drenched the central valley of Phoenix over the past month, which is plenty of moisture to excite seeds to germinate and dormant shrubs to leaf out. The well-armed branches of Ocotillo (Fouqueria splendens) are some of the first to respond to winter rains, transforming what appeared to be dead sticks into a splendid green wands.

On the desert floor, a carpet of seedlings is beginning to form. In the shade of shrubs and trees, around rocks and in swells of litter that were deposited by sheet flow of heavier rains, Burr Comb (Pectocarya recurvata) are some of the first to pop up. If we continue to be blessed with even an eighth of an inch every 10 days or so from now till March, this could be another banner year for desert wildflowers!

Tuesday, November 15, 2011

Wild Hive

We recently visited a wild hive of honeybees (Apis mellifera scutellata) nestled in a crack in lava cliffs just a ten minute walk from our house in Phoenix. Although we are warned that these bees are most likely “Africanized” and thus aggressive, I have never been chased or stung in the nine years that I’ve been observing this hive. Then again, I have never tried to steal their honey or poke the hive with a stick. These same bees are most likely the ones that are at work daily in the neighborhood, gathering nectar and pollen from our landscaping plants. Maybe they just recognize me as one of the friendly neighbors whose garden they come down to forage in every day!

Orion prefers to keep his distance from the bees. The dark cleft in the cliff is where the hive is hidden.

Friday, November 11, 2011

The Glorious Golden Scarab

We found this gilded beetle trundling in the duff along the Clear Creek Trail up near Verde Valley, Arizona a few weeks ago. The species was dubbed Chrysina gloriosa, or “glorious golden one,” one of 30,000 or so beetles in the scarab family. The Glorious Scarab is supposedly camouflaged by its gleaming exoskeleton as it feeds on the foliage of juniper trees. As grubs, they make a living chewing tunnels in decaying sycamore logs, most common in riparian habitats of southern Arizona.

My son, who aspires to be an entomologist, studies the elaborate appendages while drawing our specimen. This beetle was in its last hours, so is now preserved in Orion's insect collection.

I was surprised to find very little other information about these living jewels. Their much homelier distant cousins, the Egyptian dung beetle, Scarabaeus sacer, however, have earned the status of gods in Mediterranean mythology. As a symbol of the sun god, Ra, the scarab is plentiful in the hieroglyphics, jewelry and sculptures of ancient and modern Egypt.

If you are a Facebook user, search for Chrysina gloriosa, which has its very own fan page, and give it a thumbs up!