Frequent Flyers: Bats of Deem Hills

Go out for a stroll on any summer morning or evening, and you are likely to catch a glimpse of twilight’s most frequent flyers: bats. With superpowers far superior to those of their comic avatar, bats are some of the most diverse and abundant of Earth’s creatures. More than one out of five mammal species in the world are bats. Likewise, about 20% of the 138 mammal species in Arizona are bats, with twenty-eight kinds patrolling the night skies throughout the state, especially during the warmer months. Here on the urban fringe of Phoenix, about a dozen species are likely to flutter through while foraging.

While most of our leather-winged neighbors migrate south or hibernate during the cooler winter season, one species, the California Leaf-nosed Bat, is active year round in central Arizona. More drought and cold tolerant than other bat species, they are also well adapted to life in the desert suburbs. The California Leaf-nose is more common in neighborhoods close to natural open space like the Deem Hills, where they can find refuge in cliff crevices and old mine tunnels.

Unlike most other desert bats, the Leaf-nose is an expert at hunting ground dwelling insects and other prey, relying mostly on their excellent eyesight and stellar sense of hearing. Combined with their sixth sense of echolocation, which is augmented by their leaf-like nose flap and extra large ears, these bats can swoop down and snatch a caterpillar resting on a shrub or grab an unsuspecting beetle wandering across the desert, with laser-like precision. During the summer months, they forage mostly by night, but in the winter, it is not uncommon to see them hunting in warmer daytime hours when their prey is also most active.

Two close relatives of the California Leaf-nose, the Lesser Long-nose and Mexican Long-tongued bats, are important pollinators for agaves, saguaros and other cacti. They both have extra-long tongues, longer noses and smaller ears than their cousin, adaptations that make it easier for to them lap up nectar. Flowers of bat-pollinated plants are usually large, tubular, bright white and bloom at night, attracting bats and other night-flying visitors. While these two bat species are abundant in more southern regions of the Sonoran desert, they rarely make it this far north, where saguaros rely on many species of insects and birds for pollination. The Lesser Long-nose bat is currently listed as a federally endangered species.

Bats are fun to see in the wild, but if you don’t want to share your home with bats, be sure to seal all openings in your roof and attic with fine meshed screens. The best time to bat-proof your home is in the fall or winter when most bats migrate south or leave dwellings to hibernate in the wild.

All bats are protected by state laws; it is illegal to hunt, capture, harm or kill a bat. To help protect bats, stay away from mine tunnels and natural caves where they hang out. For lots more information on Arizona’s bats, check out these on-line bat sources:
Arizona Fish and Game Department www.azgfd.gov
Western Bat Working Group www.wbwg.org

"Other Species"

“CAUTION: You are in a natural habitat! Rattlesnakes and other species may be present.”

For many people, the mere idea of a snake elicits a reaction of fear. Attach a rattle to that idea, and that fear escalates to sheer terror. In response to these raw emotions, warning signs like this have been posted in some city parks and preserves. Casting aside a rational discussion about “caution,” “natural habitats,” and “other species,” this article aims to honor some of the non-rattle bearing species of snakes that you might encounter near Deem Hills.

Arizona is home to fifty-two species of snakes, thirty-eight of which are non-venomous or only mildly so. Venomous or not, snakes are much like humans in that their primary interests are food and finding a mate. Unlike us, our local serpents are normally not aggressive towards anything bigger than what they can eat. Since humans are much too large to waste venom on or to wrestle with, their natural instinct is to escape when they see one of us. Of the non-venomous species, about sixteen kinds may be found in natural areas and adjacent developed neighborhoods around north Phoenix.

If you see a snake, you can safely stand close enough to quietly observe characteristics that you need to identify what species you have the fortune to cross paths with. Head shape, skin color, pattern and texture, body length, shape of pupils, habitat, and whether the skin is shiny or matte are all useful indicators to notice. The time of day is also important, because many snakes are strictly nocturnal, so are very rarely seen during the day unless they were unfortunate to become roadkill. During the hottest summer months, desert snakes are primarily nocturnal, but most snakes hibernate underground during the cooler months between November and March.


Of the twenty or so species that you are most likely to see on the north suburban fringe of Phoenix, including the rattlers and coral snake, only seven species are commonly active both day and night during warm seasons. These are the Western Diamondback, Mohave Rattler, Ground Snake, Gopher Snake, Western Patch-nosed, Red Racer, and Black-necked Garter Snake.

By far the most frequently encountered of our “other species” are Gopher Snakes, one of the most widespread and abundant serpents not only in Arizona, but continent wide. They live in almost every habitat in Arizona including urban areas, but excluding alpine tundra. Gopher Snakes are often mistaken for their venomous cousins, because their scale patterns and color are so similar to some rattlesnake species, and even have black and white stripes that resemble the tail of a diamondback. Their scales are also keeled rather than smooth, and have a matte finish like a rattler. Distinctive differences are at both ends of the Gopher Snake. A good look at the tip of the tail (no rattle) and head (slender, not bulky and triangular) should set your mind at ease. If you can see their eyeballs, you might also notice that Gophers have round black pupils rather than vertical pupils like the rattlers. Gopher Snakes grow huge, up to nine feet long, which can be alarming, but we are way too big for them to eat, so rest assured that these slender beasts would not try to constrict and try to swallow a human or your dog.


Like many snake species, Gopher Snakes make excellent pest control, that is, if you don’t consider them to be a pest. They’ll eat rats, mice and ground squirrels, as well as the occasional rattlesnake and its eggs. Many other snake species eat termites, scorpions, spiders and centipedes, some of the common desert critters around home that we tend to have negative reactions to.

If you see a snake of any kind, the best plan of action is to leave it alone and walk away. Most likely, it will slither away to safety, as they know that we are far more dangerous to them than they are to us. Homeowners in Stetson Hills who wish to have any type of snake removed from their property can call neighborhood herpetologist Mark Russell at 602-315-7978, who will gladly come to your home to capture and relocate the snake.

An excellent resource for more information on snakes is “A Field Guide to Amphibians and Reptiles in Arizona “by T.C. Brennan and A.T. Holycross. An expanded version of the guide is also found on-line at www.reptilesofaz.org.

Gopher Snake photos courtesy of Rick Halliburton.

Verdins: Avian Architects of the Desert

Photo by Richard Halliburton

One amenity you may have on your list of considerations when buying or building a new home is energy efficient construction. Long before the notion of passive solar architecture emerged in modern lexicon, one of our local avian architects, the Verdin, has been creating “green” housing for centuries, if not millenia. No, they haven’t figured out how to install solar panels, but these birds do utilize the most important components of passive solar strategies: site selection, structural orientation and insulation.

Unlike most birds, Verdins build nests year round. During the breeding season, between March and June, nests are used to protect eggs and rear their young. The rest of the year, they are used as shelters from the weather. Depending on the season, the nest will be built in a location that is best suited for keeping warm or cool. In winter months, a south-facing sunny location is chosen, with the entrance oriented away from prevailing winds to keep warm. During warmer months, they will move to a north-facing shady area with the entrance oriented towards cooling winds. The amount of insulation can also be adjusted by type and thickness to suit the season.


Working together, mating pairs build hollow oval-shaped homes about the size of a cantaloupe. Males build the outer shell using thorny twigs and grasses. Females take care of interior design, lining the nest with a soft inner layer of leaves, feathers, fur and spider-webbing. Usually the nest is attached among the outer branches of a large tree or shrub with an easy flight path to the entrance. Look closely at one of these balls of sticks, and you’ll see a small hole near the bottom of the nest. Verdins prefer to build along washes where food is more abundant, but are also common in landscaped suburban neighborhoods. A busy pair may build more than ten nests over the course of a year!

You are more likely to notice a Verdin nest than the actual bird, even though they are among the top ten most abundant species in annual regional bird censuses in the Sonoran desert. On a typical sunny morning, the loud whistles and chirps of Verdins are some of the dominant bird calls echoing across washes and green belts around Deem Hills. If you follow your ears to find the song’s source, you might be amazed to see how tiny they are, less than five inches long with a wing span just over six inches.

If you’ve never noticed them, that is not surprising, since Verdins are also listed in Sibley’s Guide to Birds as one of the eight “Drab Gray Birds of the Arid Southwest.” Of all the DGB’s, however, adult Verdins are one of easiest to recognize, since the heads of both males and females look like they have been dipped in greenish yellow paint. The juveniles are the drab ones, being dull gray all over. In Spanish, verdin (pronounced “ver-deen”) means “green stain” or “green pond scum.” Not a very flattering description, but apparently that is what some early desert ornithologist was reminded of! A closer look will reveal rusty red shoulder patches. When not tending nests, Verdins spend their days flitting about in trees and shrubs, pecking at seed pods, fruits, flowers or branches to glean insects, spiders, seeds, berries and nectar.

If you are lucky enough to have a Verdin build its nest near you, let it be an inspiration to make your own home more energy efficient and perhaps a little more comfortable!

Going Native: Plant Pairings for Your Home Landscape

If, like me, you moved to Phoenix from a cooler, wetter climate, adapting your ideas about what your front yard should look like to the Sonoran Desert can be challenging. Fortunately, there are plenty of resources to help you in the transition from a water-hogging bluegrass lawn and perennial flowerbeds to a beautiful desert adapted landscape. The first place to look for help is your big backyard, or the natural landscape that surrounds your neighborhood. The native plants that grow here are your best allies in designing a colorful, year round, low maintenance, and water efficient landscape.

The Deem Hills is home to over one hundred species of native plants, including six kinds of trees, twenty different shrubs, eight different types of cacti, five species of grass, two vines and more than sixty annual and perennial wildflowers. While some are more suitable for suburban landscaping than others, many favorites are commonly available at local nurseries, and are easily blended with other desert adapted species from the greater southwest deserts. In our own yard, I’ve established over eighty different plants that are native to North American deserts, two dozen of which are common in the Deem Hills.

A few good “pairings” will help you create a landscape that harmonizes with the surrounding desert and won’t croak when droughts take over or the drip system malfunctions!

Ocotillo and saguaro: The unusual architecture of ocotillo makes an excellent frame for the equally dramatic saguaro cactus. Little to no extra watering is necessary to keep these two desert icons thriving. Following spring rains, ocotillos will produce a fresh crop of green leaves and bright red flowers. If you don’t have the cash for a mature saguaro, you can still find a place for a young one anywhere from four inches to a foot high for less than twenty dollars. Saguaros also pair nicely with palo verde trees, which serve as their “nurse plant” in nature.



Brittlebush and barrel cactus: Soften the robust and spiny barrel cactus with a background of velvety blue-green foliage with brittlebush. The hearty native shrub will produce abundant yellow flowers in even the driest of years, and is easily pruned by snapping the stems.


Fairy duster and Parry’s penstemon: Put these together in place of a sugar water feeder and you’ll be sure to attract plenty of hummingbirds! Both bloom throughout the spring, summer and fall, adding bright red and hot pink to the garden palette.

Globe mallow and purple three-awn grass: The drought resistant globe mallow displays a range of sunset colored flowers from pale pink to deep orange. Purple three-awn is a graceful bunch grass with deep purple flowering heads and bright green leaves. Both of these natives are great alternatives to fountain grass and African daisies, both non-natives that tend to invade wildlands.

Poppies and lupines: Look for a desert wildflower seed mix that includes Mexican gold poppy (Escholtizia californica ssp. mexicana) and arroyo lupine (Lupinus sparsiflorus). Both are abundant in the desert islands of Phoenix. Be sure to sprinkle the seed in the fall (late October-November) so that they will germinate and bloom by February or March. Once these get established, they will seed themselves for future spring displays.

The Deer of Deer Valley

Have you ever wondered when the last time was that anyone saw a deer in Deer Valley? Or where there are deer nearby today? Or even, come to think of it, what is Deer Valley and why was it so named?

The icon that graces some of the local street signs and school district letterheads comes from a petroglyph hammered into boulders at Deer Valley Rock Art Center in Hedgepeth Hills, just two miles south of Deem Hills. Best viewed in early morning light, the one foot high by two foot wide glyph of two sparring bucks glows soft orange against the dark basalt rock. This is the true origin of the modern name, Deer Valley, for though there were certainly deer here up to fifty years ago, there is no reason to believe that they were any more abundant here than in other nearby areas. The vast petroglyph site, however, is very unique.

For reasons that archaeologists do not fully understand, people chose to mark their passing at Hedgepeth Hills for thousands of years, including about a hundred petroglyphs (out of over 1500) that appear to be renderings of game animals. For the various tribes of ancient people who lived around Deer Valley for over ten thousand years, Skunk Creek was likely an important traveling route, and was also a lush riparian corridor running free from its source in the hills north of the town of Anthem, to its confluence with New River near 73rd Ave. and Greenway. The summit of Hedgepeth Hills, which rise from near the banks of Skunk Creek was probably an excellent spot to survey the creek and surrounding landscape for deer.

With Skunk Creek passing just east of Deem Hills, it is likely that small herds used to wander through, perhaps as recently as fifty years ago, before the area was devoured by suburbs. Although the modern Deer Valley, which spans from the CAP canal to Greenway and east to west between 20th Street and 51st Avenue, is unlikely to support any mule deer today, they are surprisingly widespread in the desert southwest wherever native vegetation still thrives and there is enough water to sustain them. Deer are browsers, preferring shrubs and tree foliage to grass, and will travel across the dry desert between water sources snacking on mesquite, fairy duster, jojoba, and other common plants. Today, if you roam a bit further east from Deer Valley to the McDowells and Cave Creek, north to Lake Pleasant or west to the White Tanks, you can find mule deer browsing contentedly on mesquite, or lapping precious water from a pothole after a good rain. South Mountain is also a large enough refuge to sustain a small deer population

Deer Valley Rock Art Center is just half a mile west of the Walgreen’s at the intersection of Deer Valley Road and 35th Avenue. They are open to the public Tuesday through Sunday from 8 am till 2 pm. The modest fee is well worth a morning visit to view the deer of Deer Valley, and to learn more about the ancient peoples and natural history of the area.

Cat Tracks

On an early morning walk up a neighborhood wash after a monsoon rain, I was lucky to cross paths with a bobcat. There were its tracks, fresh prints in the mud, a little less than two inches in diameter with characteristic three-lobed pads. Too large for a domestic cat. The lack of claw marks is another clue that this print was not made by a domestic dog, fox or small coyote, other creatures that commonly cruise the washes. I scanned the corridor and nearby shrubs, hoping to catch a glimpse of this beautiful spotted wild cat, but if it was still around, it was well-camouflaged in leafy shadows.

Several neighbors have been luckier than I, capturing candid photos of bobcats roaming their yards, resting in shade under cars, perched on fences and even lounging on their patios! About double the size of an average domestic cat, the local subspecies, Felis rufus ssp. baileyi, is leaner and lighter colored than stocky northern varieties of bobcats. If your home is adjacent to open space, your chances are higher for seeing desert wildlife, but many species, like the bobcat, are attracted into urban and suburban neighborhoods because of abundant prey.

Photo by Geena Clark

When it comes to finding food, especially for a mom cat with a hungry litter of kittens, hunting around a neighborhood greenbelt is like hitting the fast-food take-out lane. Rabbits, quail, doves, wood rats, rock squirrels, and maybe a fat lizard or two are all on a bobcat’s dining menu. Bobcats will hunt when their prey is most active, which is usually dawn, dusk, or at night. If you are worried that your small dog or cat might look tasty to a bobcat, these are good times to keep vulnerable pets indoors, although they much prefer rabbits and doves to other carnivores.

photo by Richard Halliburton

Are the cats that have been seen recently several or all the same one? We don’t know, but we do know that bobcats are extremely territorial, and rarely range within each other’s turf except to satisfy the urge to mate. Males will roam into several females’ territory, helping to insure that we continue to have bobcats around. Those that survive kittenhood are booted out of their mom’s den after about six months of training in the bobcat arts of cryptic lounging and hunting. Territories are well delineated by scent marks and scratching posts. Depending on prey availability, one bobcat will claim anywhere between 2 and 40 square miles. On the suburban fringe, where prey is very abundant, we may support a denser population of bobcats than the adjacent undeveloped desert.

For many people, a chance to view desert cats and other wildlife from the comfort of our back yard or living room window is one of the benefits of living close to natural open space. The Arizona Game and Fish Department website, www.azgfd.gov/urbanwildlife, offers lots more information about our wild feline neighbors, including a video. But keep your eyes peeled for the real thing on your early morning and evening walks. And be sure to check your patio too!

Desert Monsoon: The Fifth Season

Unlike much of North America, where each passing year is marked by four seasons, the Sonoran Desert is blessed with five, although some of us might claim that it is all one long summer! The fifth season is our summer monsoon, a stormy season that drenches the desert with torrents and flash floods. Even though it is hotter than heck, this is the most vibrant of Sonoran seasons, the one that defines the region.

Monsoon season generally begins in mid-July and lasts through mid-September. This follows a hot, dry summer that stretches from May through early July, when sane people migrate to more hospitable climates. Monsoon is an Arabic word meaning “shifting wind” and is technically not related to rainstorms. The Sonoran Monsoon marks a time when prevailing winds shift from westerly and northwesterly, to southerly and south easterlies coming from tropical and subtropical regions in Mexico. This is partly generated from the “Bermuda High” that creates hurricanes in the Mid Atlantic Ocean. At the same time, as the desert heats up and hot air rises, a vacuum, or low pressure zone, is created that sucks up moisture from the south. When the air becomes saturated, huge cumulonimbus clouds form, erupting into spectacular downpours and lightning storms that make awe-inspiring entertainment for any sky watcher.

Haboobs, gustanados, macro- and microbursts are some of the wild winds associated with monsoon season. When air from an approaching thunderstorm hits the ground, a massive dust storm rising up to 3000 feet from the desert floor and lasting up to three hours may shroud the landscape. This is a haboob. Gustanados are large dust devils originating from the ground, creating clouds of dust that sometimes look more like smoke. Micro and macro-bursts are powerful downward funnels of air that can create sudden winds up to over 50 mph. The difference is in size, with macro-bursts flowing more than 2.5 miles from their center and lasting 5-20 minutes. Microbursts cover smaller areas for shorter times. When you wake up to a landscape of uprooted trees, it is usually the gustanados or downbursts that are to blame.

Although the winds may be destructive, a monsoon thunderstorm also brings welcome relief from the heat, cooling the air by twenty degrees or more in a few minutes. The rains, however, are spotty, leaving some parts of the desert bone dry, while bringing downpours to other areas. Even if our neighborhood receives no rain at all, a storm over Deem Hills could result in flash floods in small arroyos and nearby Skunk Creek. An average storm will drop 2 inches of rain where it falls, or a quarter of the average annual rainfall in the Phoenix metro area of about 8 inches!


Summer rains also bring new life to the desert. We are gifted with a second season of wildflowers, featuring bright orange Arizona poppies (Kallstroemia grandiflora). These are not poppies at all, but are more closely related to creosote bush. Hornworms, the larvae of sphinx moths, and other caterpillars may also emerge in abundance. Butterflies break from chrysalises. Toads wake from summer hibernation in cool burrows to mate and lay eggs in pools created by rainstorms. People are wakened from summer torpor as well, with hope for a cooler fall season. This is a good time to start planting a winter garden.

For more information about monsoon weather and ecology, check out “A Natural History of the Sonoran Desert,” published by the Arizona Sonoran Desert Museum in Tucson, or pull up the ASU Dept. of Geographical Sciences and Urban Planning meteorology webpage at http://geoplan.asu.edu/aztc/monsoon.html