Tuesday, October 27, 2009

Out My Window

Costa's Hummingbird (photo by Richard Halliburton)

I've been keeping a list of all the birds my cats and I have been watching from my office window, or sitting on our front bench just outside the window. The list now has more than two dozen species on it, and growing every day! Just this morning, I spotted a Sharp-shinned Hawk cruising over towards the wash.

Roadrunner (on the road!)

Boat-tailed Grackles, male (on top) and females (below)

Here are the rest (asterisks are birds I've seen in my yard or cul-de-sac in the past couple of weeks):
Mourning Dove*, Rock Dove*, Inca Dove, Great-tailed Grackle*, Mockingbird*, Costa's Hummingbird*, Anna's Hummingbird, Black-chinned Hummingbird, Bewick's Wren*, Canyon Wren*, Cactus Wren*, Yellow Warbler, Yellow-rumped Warbler*, Townsend's Warbler*, Orange Crowned Warbler*, Bell's vireo*, Say's Phoebe*, Harris' Hawk*, Common Nighthawk, Great-horned Owl*, Gamble's Quail*, Gila Woodpecker*, Black-throated Sparrow, White-crowned Sparrow, House Finch*, Song Sparrow, Blue-Gray Gnatcatcher, Verdin*, Canyon Towhee*, Roadrunner*, Curve-billed Thrasher and believe it or not, a stray Great Blue Heron! That one was perched on a neighbor's rooftop, probably on its way between Lake Pleasant Reservoir and neighborhoods north of year where people glide around on pontoon boats from their back yards. Yes, right here in the suburbs of Phoenix!

Arrowhead Ranch (neighborhood south of Thunderbird Mountain 3 miles from where I live as the heron flies)

Thursday, October 22, 2009

First Bloom

17. What spring wildflower is consistently among the first to bloom where you live?

Most people would probably say California poppy, because it is one of the showiest flowers in the Sonoran Desert. But the true answer is Comb Nut, a teeny tiny forget-me-not flower. Pectocarya is the Latin name for this group of annuals, which are only a few inches high, with flowers barely an eighth of an inch in diameter. When there has been a wet winter, the desert becomes carpeted with these plants. If the desert looks green, it is usually Pectocarya, not grasses, that are responsible. The common name is a translation of the Latin, referring to the tooted margins of the nutlets or seedpods.

California poppies actually peak about a month after Pectocarya are first out, anywhere between late February and mid-March, depending on the winter rains.


16. From where you are reading this, point north.

Spending a lot of time outdoors, watching the sun move across the sky, shadows shifting and stars circle around Polaris, I can usually do this without a GPS or compass. Birds do it. Butterflies do it. Cows do it! Bees do it. I'd like to believe that if I ever got left out in the middle of nowhere (or everywhere, depending on your perspective), I, too, could find my way back home using these pieces of information. Tom dialed up the compass on his watch anyway to confirm my sense of direction and I was right on!

Friday, October 16, 2009

Homogenous Eclecticism

Lantana from South America

15. What are the major plant associations in your region?

In my lifetime, I've lived in at least eight different major ecosystem types, from the Pacific northwest Douglas Fir forests to the mixed hardwood forests of northern Illinois, and now to the Sonoran Desert. Maps for the larger plant associations or communities can be found in any ecology or plant geography textbook. Here in Phoenix, we inhabit a transition zone between the hilly Arizona Uplands, dominated by saguaros and palo verde and the broad flats of the Lower Colorado River Valley division of the Sonoran Desert, which gives us miles and miles of creosote and bursage. Anywhere you venture in natural areas within 50 miles of where I live, you will find these plants. The thousand or so other species occur in pockets, arroyos, at springs and on special rock outcrops along with these four dominant species. Brittlebush is another I would name as ubiquitous, but mostly because it is a reliable drought tolerant pioneer, able to drop in almost anywhere there has been a disturbance, especially in the Uplands.

But the plant association of the suburbs has not been mapped. What is in the wild and what we have transplanted into our suburbs is an entirely different assemblage of plants than the natural areas that have accidentally or intentionally been preserved. The suburban plant association is an eclectic collection of species gathered and cultivated for landscaping from all over the globe. We have euphorbias, aloes and gazanias from Africa; giant cereus cacti, lantana and bougainvillea from South America; acacias, senna and eucalyptus from Australia; oleander, olives and chaste tree from southern Europe. From China we've imported rose vines and jasmine. From other regions in North America we bring Texas sage, red yucca and candelilla. We even have an endemic from Afghanistan, Pinus eldarica, or Afghan Pine.

In fact, if you thumb through a handy guide distributed by our regional Water Conservation Committee, Landscape Plants for the Arizona Desert: Guide to Growing More tThan 200 Low Water use Plants," nearly half of the recommended species are not native to the local region. And so we have created our own kind of plant association here in the suburbs. Although Sonoran natives are still included in the melieu...palo verde and mesquite are favorites in most parking lots...the dominant creosote and bursage that occupied the suburban landscape before they were bulldozed away are largely missing. Saguaros remain as occasional icons of the native landscape, but often don't survive the process of development.

I've often wondered what would become of the Suburban "division" of the Sonoran Desert flora if humans suddenly left, irrigation was ceased, and all of these species were left to fend for themselves in these foreign soils. Would they thrive or die off? Would they adapt and invade? Would they eventually mingle and reproduce well enough with the natives in the wild to create a whole new plant association?

Lilac Vine from Australia

Some have already shown their adaptability. We usually denigrate them by calling them "noxious weeds." Bermuda grass, fountain grass and African sumac are a few of the species that do quite well on their own here, to the bemusement of land managers whose predecessors may have brought them here. Others die off quickly without a drip. Our neighbors abandoned and foreclosed on house is surrounded by skeletons of lantana and ailing Queen palms.

Either way, I quite enjoy all of them, especially when I'm walking in the morning, and notice the also introduced swarms of honeybees (from Europe) feeding on daleas (from the Chihuahuan desert), and hummingbirds (native) slurping nectar from red yuccas (Chihuahuan), house sparrows (from Europe) congregating in fig trees (from Africa and China), and cottontails (native) feasting on Bermuda grass (African). The landscape changes slightly every fifty feet or so, depending on the preferences or inherited landscape of the current homeowner. Perhaps these variations could be called the Bermuda/Palo Verde/Lantana association; or the Texas sage/willow acacia association; or the senna/mesquite association. This wonderfully eclectic collection of plants is, however, uniquely homogenized into our own humanly assembled plant community, and it is spectacular!

Wednesday, October 7, 2009

On the Edge

This photo was taken a few springs ago in Burro Creek in Western Arizona. Burro Creek is in a wilderness area. Southeast of there, on the horizon in the photo, is a mountain of mine waste from a copper mine near Bagdad, Arizona.

The "Where You At" series asks this question:
14. What species have become extinct in your area?

As a biologist, I would rewrite this question to ask:
What species are currently at risk of extinction in your area?

I rephrase this because extinction is actually the norm for life on Earth. Paleontologists estimate that more than 99% of all species that have ever existed are now extinct, victims of massive events that changed the planet's climate. Six major extinction events are recorded in the annals of biological life, the last of which is occurring today. Right now. Extinction is generally a very slow process that occurs over hundreds or thousands of years. When populations of a species become scattered, small and/or concentrated, that is when a cataclysmic event can wipe them out forever.

In the state of Arizona, the Fish and Wildlife Service has fifty four species of animals and seventeen species of plants listed as threatened or endangered, or at risk of becoming extinct unless carefully managed and protected. In addition to these "T&E" species, there are hundreds more that are considered "rare" or "sensitive," meaning that populations are stable now, but that habitat and distribution is limited. Most often the causes of rarity for TES (Threatened, Endangered or Sensitive) species are habitat fragmentation, habitat destruction, or, as in the case of many fish species, radical habitat alteration. Today, most significant changes to habitat are due to the activities of humans.

So, the answer to the first question is, "Too many to count or record!" But we could just give one recent example of wolves, which used to range into the Phoenix area, but have been extirpated by government sanctioned hunting so that they now occur only in the most southern ranges of Arizona. Ironically, their existence in Arizona today is also courtesy of the same government that set out to exterminate them. Only now we are attempting to reintroduce them. Unfortunately, at the same time, there are still people who would rather ensure their extinction, a mindset I cannot fathom.

The answer to the second question could be "all species" if you are inclined toward catastrophic thinking. But I am not so morose. I believe that life will always find a way. After each of the major extinction events, life has always evolved into more diverse, abundant and magnificent forms. The biological communities we have today are entirely different than the ones that thrived right here one hundred million years ago. The current extinction event will most likely play out in a similar way. Whether humans are around to observe what happens a thousand years from now is a big question that we cannot answer. Rather than descend into speculative discourse on the Holocene extinction, I'll just feature two species that are on Arizona's list of rare plants.

One is Agave murpheyi, or Hohokam agave. The most interesting fact about this species is that they are documented in the wild only where former agricultural areas were managed by ancient peoples that once subsisted in the Phoenix area. The Hohokam people used the plant for food, fiber and trade. Today, these plants are cultivated at local nurseries for ornamental purposes, so "trade" in Agave murpheyi continues in earnest! In fact I "traded" a five dollar bill for one that now grows in my yard, shown above. The wild populations that remain may have been originally established by Hohokam communities from young plants or "pups" that were imported from Mexico. So here is an example of a species we dub "rare" in our area because there are few small scattered populations, but the reason these populations exist at all is because people imported them! Very interesting indeed!

Another rare plant that I have visited is Purshia subintegra, or Burro Creek Cliffrose. There are four populations known only in Arizona, the largest of which is in a heavily populated area just north of Phoenix in the Verde Valley. Burro Creek Cliffrose is listed as endangered, and is threatened by urbanization, mining, overuse by cattle and burros, road construction, off-road vehicle traffic and extended drought. They are also limited to habitats where there are limestone outcrops. Unlike the Hohokam Agave, there are no known uses to humans other than possibly as an ornamental landscaping plant. But because of its intrinsic value as a unique species, humans are working to ensure that this species does survive in the wild, by salvaging plants that wind up in the path of urban development and by cultivating them for reintroduction into native habitat. The pictures I have of this plant were taken in Burro Creek, south of Kingman. The shiny blister beetle that is visiting the flowers coexists, and may be partly dependent on this plant. Such is the web of life!

So it is on both ends of the spectrum that human civilization influences individual species and entire biological communities. We wipe them out. We preserve and facilitate their continued existence on Earth. How we conduct our lives, both as individuals and communities, will determine the fate of not only our own species, but of millions of others that creation/evolution has graced our planet with.

More information on TES species in Arizona can be found at the US Fish and Wildlife Service website:

And at the Arizona Natural Heritage Program page for the Arizona Fish and Game Department:

Saturday, October 3, 2009


When you live in the Sonoran Desert, you are likely to become more acquainted with dawn if you enjoy spending time outdoors, because this is the easiest way to tolerate or avoid the heat much of the year. May through October are months that have highs in the hundreds most days, so getting out before the sun comes up is what many hikers, bikers and runners do to avoid heat stroke and exhaustion. Five in the morning works well. I've always been an early riser, but six years living in Phoenix has led me to experience more dawn hours than all the rest of my years.

By 5:30 most mornings, 6:00 at the latest, I am up and outside either hiking or running. The hiking wouldn't happen if I didn't have a friend to meet twice a week. Caroline and I, plus dozens of other fitness-minded people avoiding the heat, begin our bi-weekly trek often by headlamp, like mountaineers on an alpine start. You can see the little lights bobbing along the switchbacks up the well trod trail leading up Thunderbird Mountain, a silhouette against the urban lit sky rising five hundred feet from the valley floor. On mornings around the full moon, we can navigate by moonlight.

At this time of year, the morning sky begins to glow about half way up the trail, backlighting peaks to the East. We often witness the magical moment when the orange crest of the sun bulges up out of the hills. Colorful city lights wink beneath the orange glow until the sun fully emerges, drowning them out.

Besides the cool air and light, dawn is a time when many desert animals are most active. Owls, nighthawks and bats are making their breakfast flights. The occasional snake moves off the trail out of our way, disappearing into rocks. Coyotes howl and flow through the prickly shrubs on their way to a daytime resting spot. Black throated sparrows, towhees and cactus wrens call to each other, announcing their territory or calling for mates.

For many hikers, dawn is a ritual, a prayer. We greet the day with hope, chatter about our joys and woes, much as the birds may be doing. Some run. We are grateful to be healthy and able to walk the rocky trail, feeling our hearts beat, breathing deeply desert air. Each dawn is a gift.

Friday, October 2, 2009

Geologic Forces

Back in April I started exploring questions from a series called "Where You At?" (see my April 10th post, "Agua Dulce"). Returning to that series, we are asked this question:

#13 What primary geologic event/process influenced the landform where you live?

This question took me a long time to think about. Perhaps this is because the idea of landform is a bit difficult to suss out in a place where the land has been bulldozed and paved in a way that makes it tough to recognize the natural form of the land. But therein lies the answer! Humans are the primary geologic force at work here in Phoenix. The valley has been transformed from a vast undulating desert of bajadas and arroyos into canals, dams, bridges, reservoirs, mines, and sprawling development that recent reports declare we will add 400 more miles of highway to by the year 2050! Four hundred!!!

Volcanism has also had a big influence on the landscape here. Where the land has not been reworked, paved over, and re-landscaped, our neighborhood is circled by a ring of six hundred foot high hills that rise above the valley floor. Like many of the surrounding desert peaks, Deem Hills is made of rubble leftover from volcanic eruptions that occurred between two and five million years ago, which is relatively recent by geologic standards. The dark rocks, called basalt, glow deep purple and orange in the evening sun. Basalt is basically cooled off lava. Here, many of the rocks have pits and holes in them, evidence that the lava was almost frothy when it flowed and then quickly cooled, leaving small air bubbles in the rock.

Ironically, water has had an equally large influence on the landscape here in one of the most arid regions of North America. Whenever rains fall, flash floods and sheet flow move thousands of tons of rock, sand and silt, gradually eroding the hills. Bajadas are the alluvial fans, or outwash of debris that flows out of the mountains creating a gently sloping landscape at the base of the hills. Arroyos are the beginnings of canyons, like the Grand. Over time, water and wind probably move more earth than any other geologic force other than plate tectonics.

But right now, humans may outweigh even plate tectonics in the effects on landform when you count the accumulated impacts of our civilization on the movement of air and water combined with actual earth moving here in Phoenix.

Thursday, October 1, 2009

Black Widow Refuge

My back yard is a refuge for black widow spiders. While exterminators regularly spray my neighbor's yards and homes with pesticides, I've chosen to let "pests" live in our yard, weaving webs, making nests and providing food for the numerous lizards and birds that also visit. (Although I will admit that when the termites start drilling into our walls, I call the exterminators!) Perhaps it was Charlotte who convinced me that spiders deserve to be allowed their quiet livelihood in the yard, or perhaps my ecological sensibilities that respects the necessary role that all creatures play, even in the suburbs. Whenever I see a gleaming black widow with her slender legs and red violin I am fascinated rather than repulsed.

This may seem reckless or foolish to most people, but so far, the spiders have obliged by keeping out of sight during the day, and sinking their tiny teeth only into edible prey, such as crickets that also enjoy refuge here. Once in awhile I'll catch one resting in it's tangled web in a plant on the patio at night, but as soon as it senses my presence, it scurries out of sight, knowing rightly that I am far more dangerous to her than she is to me. Out in the log pile, I reach in with gloved hands to gather wood for a new moon fire, setting aside the marble sized egg sacs full of soon to be spiderlings.

So far, we have not experienced any grotesque infestations of roaches, ant, crickets, spiders or scorpions, the "pests" that support a thriving exterminator industry in Arizona. Yes, all of these creatures are here, and as long as they stay outside in the back yard refuge, we coexist peacefully. I like it that way.