Saturday, May 23, 2009

Summer Skies and Scorpions

According to Greek legend, the venomous sting of a scorpion killed Orion, the great hunting god. One of many stories about Orion’s fate tells that the Greek goddess Artemis cursed him with the fatal sting because she was jealous of his courting Dawn, the goddess of morning. During the summer, the constellation Orion can be seen lying down on the eastern horizon, greeting his lover just as the sun rises. At the same time, the constellation Scorpius sets to the west. Likewise, Orion is most visible in the night sky in mid-winter, opposite Scorpius, which some say is because they are carefully avoiding each other.

During mid-summer, stars that make up the sweeping spiral tail and claws of the constellation Scorpius dominate the southern night sky. These are clearly visible even around the light drenched city of Phoenix. At the heart of Scorpius shines Antares, a huge star 300 times the size of our sun. The name Antares is Greek for “rival of Mars,” because they both glow red and are about the same size to our eyes when viewed from Earth. However, if Antares were the center of our solar system, it would swallow Mars and reach almost to the planet Jupiter!

Summer nights are also the most likely time that you will see a living scorpion in the desert, since they are nocturnal and more active during warmer months. Scorpions have been very successful, having survived over 350 million years on our ever-changing planet. Of the 1500+ species known world wide, 90+ are found in the U.S.; about thirty live in both wild and tamed regions of Arizona. Three of these are common, and likely to be seen in the Phoenix area if one cares to look for them. The most spectacular but least common of the three is the giant hairy desert scorpion, a dark-skinned beast that grows up to six inches long. Although frightening to look at, this species is not very toxic to humans. But if you were an insect, lizard, spider, or other scorpion, you would definitely want to stay out of their way.

The less intimidating striped devil scorpion grows to less than three inches long, and is blonde or tan with broad dark stripes down the length of their backs. This species is also not life threatening to humans, though the sting can be very painful.

The bark scorpion is the only one in our area that is highly toxic to humans. They are also blonde and similar in size to the striped devil, but lacking the stripes. A well-aimed sting from a bark scorpion can immobilize a 250-pound man, and could be fatal to a small child, unhealthy adult or small pet. The powerful neurotoxin causes numerous symptoms including a sharp tingling sensation, numbing, uncontrolled breathing, muscle spasms, and general aching. Some people suffer allergic reactions to the sting as well. These are the kind that are most common in our neighborhood.

My friend Christy was kind enough to bring me the above photographed specimen that she caught in a jar in her back yard. The wildlife watching was fun for the family until one morning when 22 baby scorpions appeared on momma's back. Something about all that neurotoxin freaks most people out. But I am delighted to have a friend who cares enough to show me local wildlife rather than just flushing it down the toilet as most people would do in this case!

Fortunately, scorpions are not aggressive towards humans, and will only sting if threatened, such as when they get stuck between your shoe and your foot. They hide in rock crevices or burrows in the soil during the day, when humans are more likely to be outside. At night when they are active, it is not uncommon to see one cruising down the sidewalk or crawling on a tree trunk. If you shine a black light around your yard or in the desert on a moonless night, you will be able to easily find them glowing greenish white in the dark. Other than humans, the main predators of scorpions are nocturnal animals including snakes, mice, shrews, elf owls and other scorpions.

Although it is true that the sting of some species of scorpion can be fatal to even a very strong man, this is extremely rare. According to current medical records, there have only been two deaths in Arizona due to scorpion stings since 1968. Compared to other risks we face each day, these creatures are relatively benign. If you can overlook their venomous capability, they are fascinating to see and watch.

However, if you do not feel comfortable sharing your space with scorpions, be sure to keep your yard tidy and free of debris where they like to hide. Look carefully before you put your hands or feet under rocks, in woodpiles, or even when moving outdoor potted plants. Don’t leave close-toed shoes outdoors and avoid going outside barefoot at night. You can also have an exterminator treat your property with a special arachnid poison. Scorpions are not insects, so insecticides will not affect them. However, insecticides are useful if you want to eliminate prey that would attract scorpions to your home.

Friday, May 22, 2009

Suburban Century

#12 What is the land use history by humans in your bioregion during the past century?

I have delayed writing about this 12th question in the "Where You At?" series (begun on April 10th in my blog) because I thought I would find the time to dredge up more real numbers on the subject. Acres, decades, populations, etc. However, for the purposes of this blog, my personal observations and a few basic statistics will suffice. As a starting point, the Phoenix metropolitan region comprises ~2500 square miles of land.

Anyone who lives in the Phoenix area could make a reasonable generalization that about 50% of the current land use is dedicated to transportation needs. Or desires, if you prefer. That is to say, parking lots, roads, highways, train tracks and airports take up a staggering amount of land. This is a primary characteristic of Phoenix, other than the fact that it is in a desert. Of all the cities I have lived in (Seattle, Chicago, Fort Collins, Boulder, Colorado Springs, San Francisco), Phoenix is by far the most vehicle intensive and pedestrian/bicycle unfriendly.

But it wasn't always that way. Phoenix's humble beginnings were as an agricultural community, with citrus and cotton being the main crops and economic base, although transportation did play an important role since the beginning because large scale agriculture also requires large scale distribution. Agriculture requires prodigious amounts of water, however, so the economy of the area has changed dramatically from growing food and fiber to developing corporate headquarters, malls and housing, which supposedly require far less water to sustain. Which begs the question: So where do we now get our food? But, I digress.

The city was established in 1868. Arizona was inducted into the union in 1912. In the last 100 years, the population of the Phoenix area has swollen like a cancer from ~11,000 people to over 4 million people. We were rated as the 2nd fastest growing metro area in the U.S., after Las Vegas, over the past decade. The growth has slowed somewhat since the economic recession. A shocking 24% of the growth has occurred in the past 10 years. I have personally contributed 3 people to that statistic.

The stunning vastness of this metro area is most easily comprehended from the air or a mountain top at night. Electric lights spread to the horizon in every direction if you climb to the top of Squaw Peak, for instance. This photo was taken one early morning from the top of our more humble neighborhood high point, Thunderbird Mountain.

But, lest I forget, Phoenix and the other two dozen or so cities that comprise the Valley of the Sun's contiguous suburban landscape, have dedicated a reasonable amount of land to open space, including one of the nation's largest city parks, the 16,500 acre South Mountain Park, which you could just about go backpacking in, except I don't think they allow overnight camping.

This is a view from the mountain preserve in my "backyard," a 5 minute hike up the road.

And we also have the standard urban delights of universities/colleges, museums, ballparks, theatres and zoos. Plus a few military bases. To support all of this, I would bet that you could put at least a single digit percentage on the land use dedicated to our energy needs, including a nuclear power plant (see my December 1, 2008 entry). And our water needs (reservoirs and canals plus treatment plants).

However, the majority of land use here now is lots and lots of malls, massive corporate offices, lots and lots of tract housing (much of which is seasonally vacant or for sale now), and huge acres of asphalt. There are also a few remaining citrus groves and cotton fields on the fringes.

Wednesday, May 20, 2009


Common Baskettail Dragonfly, photo by Karolyn Darrow

Every so often we discover an unexpected gem in the Phoenix megalopolis. Last weekend, believe it or not, we found the most amazing wetland, right in the middle of the suburbs! The Gilbert Riparian Preserve, southeast of the crossroads at Guadalupe Road and Greenfield Avenue, is a 110-acre park with eight huge manmade ponds that were created and vegetated with native species as part of a water reclamation program for the city of Gilbert.

We got up very early on Saturday morning to go oding at the preserve. Arriving at 7:00 am after an hour long drive, we joined about a dozen other folks, ranging from ages 5 to 85, to learn about dragonflies. Since these fascinating bugs are in the taxonomic order Odonata, the sport of dragonfly (and damselfly) watching is called oding! Ya learn something new every day. (The excellent photo above of a newly emerged dragonfly was actually taken near Washington D.C. by my sister. That species is native to the Eastern U.S., so is not fund at the preserve.)

Mexican Amberwing at the Preserve

With the help of our knowledgeable guide, Bob Witzeman , we spotted and identified eight species of Odonata, including the Mexican Amberwing, Blue Dasher, Flame Skimmer and Wandering Glider. They have the coolest names! Interestingly, dragonflies and their more slender relatives, damselflies, did not have official common names until 1996. Since then, there has been a proliferation of dragonfly field guides, of which we now own two. Hey, in our house, you can never have enough field guides!

As a bonus, we were also treated to a flotilla of fuzzy ducklings, a turtle, a flock of black-necked stilts, avocets, egrets, great blue herons, geese, and black-crowned night herons. But best of all, I was so happy to see lots of families and children enjoying the outdoors early on a Saturday morning. There were probably at least a hundred people out bird-watching, photographing, fishing, hanging out, walking, running, dog-walking and, of course, oding.

Orion was certainly the spiffiest oder in his new dragonfly vest!

Tuesday, May 19, 2009

Zoom and Bloom

One of the most extravagant botanical happenings in the southwest deserts is when agaves have mustered the energy to send up their flowering stalk. Their reproductive strategy is known colloquially as "boom and bust" reproduction, because the plant will live for many years as a leafy rosette, (anywhere between 3 and 100, depending on the species) and then shoot up a stalk bearing hundreds or thousands of flowers in one season. Then the entire plant dies. The academic term for this is "monocarpic perennial," which translates to "plant that lives for many years but only produces seeds once." I call it "zoom and bloom."

For the past few weeks we have been measuring a few agaves near our house every day or two to see how fast they zoom. When we started measuring the first one on April 24th, it grew three or four inches a day until a thoughtless vandal snapped the flowering stalk and put an end to the zooming. But in that week it went from 38" tall to 65" tall. The broken stalk is still alive but could not grow any taller since these plants grow from the tips of their stems (the apical meristem, if you want to speak botanese). Today we noticed that, despite the damage, the remaining buds on the lower part of the stalk are beginning to open.

We started measuring two other agaves after the sad day when the first plant was brutalized, one of the same species and one of a different species. (I confess that I haven't taken the time to identify either of them yet. There are over 300 species, and in landscaping it could be any of those, not necessarily a native to the area.) The slim stalked species like the one that got broken has topped out at 115" tall, nearly 10 feet, and is now beginning to bloom. The other is growing even faster, zooming up to 9" per day, with no sign of flower buds yet. Eyeing old stalks of the same species, I'm going to predict that it will zoom up to 15 feet tall before it blooms.

So this is what we do to amuse ourselves during the hottest May on record in Phoenix-14 consecutive days of 100+F highs.
Tune in for the next exciting installment of the Agave Chronicles next week when we begin counting flowers and recording pollinators!

Sunday, May 17, 2009

Solar Cooking

Today I set up the solar oven to bake a loaf of dilly bread. We cranked it up to about 300 F, kind of on the low side since it is partly cloudy today. I also used an egg from my friend Merrily's goose, since I made two loaves (one goose egg = two hen eggs). One was baked in the solar oven and one in the conventional electric oven. Both loaves of bread turned out great! Here is the recipe, which is an old favorite from my mom:

Dilly Bread
1 package of yeast (~2.5 teaspoons)
1/4 cup warm water
2 T. sugar
1 cup cottage cheese (heated on stove until smooth and creamy)
1 T. butter
2 t. dill seed
1 small onion or 2 shallots, minced
1 egg
2 1/2 cups flour
1/4 t. baking soda

Blend yeast with water and sugar. Stir creamed cottage cheese, butter, dill seed and onions together. Beat egg and add to cottage cheese mix. Stir in baking soda then add flour 1/2 cup at a time. The batter will be very sticky. Don't knead it, just leave in the bowl and let rise till double. Turn into buttered round casserole dish or pie pan. Bake at 350 F for ~45 minutes or till golden brown.

Tuesday, May 12, 2009

Magic Mornings

One of my favorite things about mornings here is walking into my backyard and seeing hot air balloons gliding by. There is a popular launch site just a mile to the east of us, so we see them several days a week. Sometimes they float right over our yard and we can wave to the basketful of people. The propane gushes flames, roaring like a dragon as they drift up over the hills. Usually there are at least four or five, sometimes a dozen balloons with the trademark giant saguaro on a rainbow background.

We took a balloon ride a few years ago over land that is now covered with houses and streets. The land below was a maze of dry washes with lines of palo verde and ironwood marking their traces. Black-tailed jackrabbits loped across the desert grazing on shrubs and grasses. Ravens swerved and called between our small group of balloons. There is a special kind of silence floating through the air. Riding a balloon feels like being smoke.

The ride was magical, but it is just as magical to see them from the ground, sometimes rising or setting like a giant colorful sun from behind the hill. The big wicker basket, the flames, the kaleidoscope of fabric seem part of another world, another time. Sometimes, with the world the way it is here on the ground, hot and violent in so many places, it is a great relief to be taken for just a moment into the fantasy world of ballooning.

Thursday, May 7, 2009

Migrants and Residents

#11 Name five full-time resident and five part-time resident birds in your area.

A red-tail hawk family nesting in a saguaro, one of our full-time residents

Everyone loves to deride the "snowbirds" of Arizona, the masses of retirees who winter down here where it is warm, heading north between May and October to escape the insanely hot summer. Or is it that they are residents in the north during the balmy summers, and flee south to escape the blistering cold winters? Either way you look at it, they are in plenty of good company, because hundreds of bird species use the same strategy of seasonal migration to up their chances of finding decent food year round and good nesting sites when the urge to mate urge arises. As opposed to the northern or high-altitude bio-regions where avian life is much more diverse during the summers, the Sonoran desert region hosts more winter residents. We are the south that many birds migrate to during the winter, especially for a lot of ducks and other birds seeking open water. But there are some masochistic summer resident birds that hang around here during the searing hot summer months and migrate further south during our ever so slightly chilly winters. I know of no humans who would choose such a lifestyle!

Then there are those, both birds and humans, who tough out the entire year wherever they happen to be, adapting either to the blistering heat or freezing cold, and maybe even enjoying it. I have to say that my true nature is as a winter adapted bird. I would be very happy as a chickadee, snowy owl, or ptarmigan. But here I am among the cactus wrens, roadrunners and Harris hawks that thrive in a year-round summer climate.

Off the top of my head here's my five plus five:

some Full-time/Permanent Residents:
Cactus Wren, the Arizona State bird
Gamble's Quail

some Part-timers:
Black-chinned Hummingbird-summer residents
Common Nighthawk-summer resident
White-crowned Sparrow, winter resident
American Goldfinch-winter resident
Western Bluebird-winter resident

Mud Dauber Mom

We recently observed a mud dauber wasp building her nest on our back patio. She was busy early in the morning building the last of nine cells, each of which will eventually hatch out a new wasp. I read in our Field Guide to North American Insects that in order to provide for her young, Momma Mud Dauber stuffs each cell with up to a dozen spiders. We are thrilled, because our back patio has been a refuge for black widows. The last one I spotted had spun a web right next to the door. But since the mud dauber built her nest, I haven't seen any black widows! To me, this is a great alternative to pesticides.

When we first saw her, she had just started the last cell. Within an hour, she had built it up and was ready to cap it off. Now we wait for the next generation to emerge.

Urban Trees

#10 Name five trees in your area? Are any of them native?

One of the things I've come to appreciate about Phoenix is the enormous diversity of trees growing in the city. Though the surrounding desert is mostly lacking in trees, except along watercourses, the well-irrigated urban landscape supports a lush forested landscape of trees from all all over the world. There is even a Department of Urban Forestry for the City of Phoenix that promotes planting trees in the city.

My favorite five around here are:

Desert Willow: This one is native to the Sonoran Desert, growing along washes all the way from Grand Canyon down the Colorado River drainage to the southeast corner where Arizona borders Mexico. They are not willows at all, but have long slender leaves like many willows. Unlike true willows, which are mostly wind pollinated, Desert Willows have huge showy orchid-like flowers that attract many types of pollinators. They are in full bloom all summer long, from April through October, defying the stifling heat and periods of drought that send many desert plants into dormancy.

Jacaranda: This is a tropical relative of the Desert Willow that is imported from Brazil. Huge clusters of extravagant bright purple flowers contrast with elegant white trunks and bright green fern-like leaves. These thirsty trees are not exactly a great choice for desert landscaping, but there are many of them established especially in older parts of the city and they are gorgeous in bloom!

Ironwood: A hearty native famous for very dense wood, ironwood is another spectacular bloomer. These ones burst into a cloud of pale violet about now, and are so pretty in the early morning light. I haven't succeeded in capturing the ethereal quality of flowering ironwoods on film or microchip, but this is sort of what they look like.

Sycamore: In canyons and along the big rivers, sycamores are the giants of the native desert trees. Some of the older ones have trunks up to 3 feet in diameter! These are one native you don't see so much in landscaping, but I'm not sure why. I think they need a little more shade than is available in the city to do really well. This picture was taken along the Upper Salt River. The great white trunks are silouetted in the desert side canyon, survivors of the early days of the Salt River Project, which removed most of the great cottonwoods and sycamores along the river because they "used too much water."

Washington Palm: I love these guys. And they are native! There are a few wild remnant populations in the state, but now they are more abundant in city than in the wild. One of the coolest things about palm trees is that they are most resilient in the high winds of monsoon season. Last fall when we had a huge storm that brought down huge old pines and eucalyptus trees all over downtown Phoenix, the palms just laughed and remained standing. I love the way they look with their skirts, but people are obsessive about shaving them off in the city because they don't like the fact that birds and rats like to nest in them.

Wednesday, May 6, 2009


#9 On what day of the year are shadows the shortest where you live?

The June solstice, usually on June 21st in the Western hemisphere, is the day when shadows are shortest here in Phoenix, but this can vary slightly depending on the calendar year. If we lived in the Southern hemisphere, we would observe the shortest shadows on the December solstice, December 21st. As the sun rises higher in the sky and the days become longer, and warmer (the forecast for Phoenix is 104 F on Friday this week!), the shadows become shorter. A good shade tree is a blessing.

The path of the sun, or ecliptic, is the basis for many ceremonial observances in all cultures. June weddings (in Euro-centric cultures like ours) were originally celebrated around the solstice, symbolic of ancient pagan observances of this celestial event as the marriage of the God and Goddess, or Heaven and Earth, a union that creates the fruits of harvest. I wonder if December is a popular time for weddings in South America and South Africa for similar reasons?

One of my favorite exhibits about the ecliptic, besides the cool archaeological monuments like Stone Henge and some rock art in the southwest, is a contemporary design at the North Mountain Visitor Center in Phoenix. Although I've been aware of the ecliptic and observed the equinox and solstice dates for decades, this exhibit really enlightened my understanding of the dramatic variation in where the sun rises and sets over the year. Seeing this on paper is not the same as standing in the middle of the exhibit and feeling it.

Another fun exhibit or artwork on this theme is a human sun dial at Life Lab near the UCSC campus in Santa Cruz, California. When you stand in the middle of the circle, your shadow points to the solar time of day. I've got some ideas to create a pebble mosaic like this when I have a big enough yard to accommodate one.

Archaeoastronomy, or "the study of how people have understood the phenomena in the sky, how they used phenomena in the sky and what role the sky played in their cultures" is fascinating to me. I wonder how our modern urban cultural myths might change, or have been changed, as we've become less and less tuned to the sun, moon and stars in our daily (or nightly) lives And how would it feel if we returned to judging the time of day by the length and direction of our shadows, rather than using a clock?

Tuesday, May 5, 2009

First Grade Wisdom

I've been reading Deepak Chopra's book "Life After Death" this week, which explores the idea of consciousness and death from various perspectives. There are more questions than answers on this subject, so it is an area ripe for discussion. So, just to make conversation on the way to school this morning I asked my 7-year-old son, Orion: "Why do you think people are afraid to die?" Orion thought about this for a moment, and said, "Well, I don't know, but I do know that the reason people die is to make room for more people, because if no one died, this would be a very crowded world!"
So true.

And here is Orion, who also says that he is not afraid to die, because he really enjoys living. Eating strawberries and chocolate is his version of heaven!

Sunday, May 3, 2009

Growing Season

A more successful and much larger garden than mine at The Farm at South Mountain. This photo was taken in late September.

#8 How long is the growing season where you live?

Growing food in Phoenix is a year round affair, as long as you have water, which, thanks to humongous water projects by CAP (Central Arizona Project canals) and SRP (Salt River Project reservoirs), we have been conditioned to believe we have an abundant supply of. With no significant frost, an attentive gardener can nurture veggies right through the winter solstice here. Diligent growers can also plant and harvest two seasons of annual crops, starting in August and January, according to "Desert Gardening for Beginners" by Cromell, Guy and Bradley. Most gardeners in the area take a break during the hot summer months, from June through August, to let themselves and their land restore themselves.

Timing is everything, as with most anything we do, but especially when it comes to gardening. Last year I attempted to grow squash from seed starting in October, which is way off, since these are one plant that wilts at any hint of frost. Although rare, frost does happen for a few early morning hours during December and January most years, and one morning hovering around 30F is all it takes to put an end to a hearty thirty-foot squash vine. Had I consulted the handy gardening calendar in the above mentioned text, I would have learned that planting in any month between January and July will work for squash to grow to fruit, but forget it after August. I also would have escaped the tragedies of my spring planting of frost tolerant lettuce, kale, broccoli and spinach, which all prefer the fall growing season beginning in August.

So now I'm keeping it very simple, and planted six zucchini transplants yesterday. The book says seeds should go in no later than mid-April, so I'm crossing my fingers that the month old seedlings will be okay. Since the cats have become accustomed to using the fallow garden beds as a "powder room," each plant is protected with a vine cage. I estimate that we will be blessed with an abundant supply of zucchini within a couple of months. We also have a potted herb garden with spearmint, basil, oregano, sage and rosemary to season it with. And a strawberry plant that, if we are lucky, will produce a few succulent snacks by late summer. But that one isn't even listed in the desert gardening book, so we and our suppliers, Home Depot, may be hopelessly optimistic. Thank goodness Safeway is less than a mile away!

Friday, May 1, 2009


A good day looking north from the top of Deem Hills

On the long list of things we take for granted that I've mused upon in this blog, including water, waste management services, and food supply, I probably think more about breathing than anything. On the two mornings a week that I hike to the top of Thunderbird Mountain with my faithful hiking partner, Caroline, we are able to take a 360 degree survey of our air shed at 6:00 a.m.

Some mornings, especially after a light rain coupled with wind, the view to the south is blessedly clear enough to see the silhouettes of downtown Phoenix's skyscrapers. All around, layers upon layers of desert hills circle the city. Early morning light gilds the green urban landscape. I feel good about taking a deep breath. Other mornings, we gaze out in horror at the brown smog that has settled in the valley, obscuring silhouettes, dimming distant hills and casting a ghastly haze over everything. What we see is what we are breathing, and this cannot be escaped.

A scary day looking north from the top of South Mountain

According to a recent study published by the American Lung Association in their State of the Air Report (, Phoenix, Arizona is the 9th most polluted city in the U.S., with over 100 days a year declared "unhealthy" to breathe. This is mostly from ozone, the low level smog that is created from burning fossil fuels, although many locals want to believe it is "just dust." Ground level ozone is produced when nitrous oxides combine with atmospheric oxygen in the presence of sunlight. Cars are the largest emitters of the nitrous oxides, which is why large urban areas tend to have the highest levels of this type of ozone.

I experienced the toxic effects of ozone this winter when I had a chronic cough that was not associated with any infection. My doctor prescribed an inhaler loaded with steroids to reduce the inflammation, and the condition abated within a month. But I can't help wondering what long-term effects are going on deep in my lungs. I have never smoked cigarettes, but that may not matter. Just breathing in Phoenix may create similar effects!

What can be done? This is another one of those "Tragedy of the Commons" issues that requires a cooperative effort to solve. Less driving. More walking and biking. More fuel efficient vehicles. The cumulative effects of each of our miniscule efforts does matter. So now that I'm finished writing this, I will ride my bike, rather than drive, to the grocery store to buy the organic milk and free range eggs that I need to make dinner tonight!