Ponderosa Pine Forest

Mexican blue oak foliage.

Uncommon in the monument, but worthy of mention, areARIZONA SYCAMOREandARIZONA CYPRESS. The latter is restricted to the east flank of the Rincon Mountains, steep slopes, and deep canyons, where it grows with theSILVERLEAF,PALMER,EMORY, andNETLEAF OAKS; mesic shrubs; poison oak; andCALIFORNIA BUCKTHORN. Arizona sycamore grows along lower-canyon watercourses such as Chiminea and Rincon Creeks, which drain the rugged south flank of Mica Mountain and the west flank of Rincon Peak, respectively.

As you continue to climb, the open, grassy, shrub-dotted slopes change in places to sprawling thickets, called chaparral. These are made up of manzanita and skunkbush,SILKTASSEL, evergreen oaks, and underbrush of smaller shrubs. Among the common oaks areARIZONA WHITE OAKand, on drier sites of the Tanque Verde range,SHRUB LIVE OAK. The oaks furnish protective cover, browse, and acorns for deer and other mammals and birds, and are of greatvalue in retarding soil erosion on steep gravelly slopes.

Turpentine-bush, a member of the sunflower family.

POINTLEAF MANZANITAis especially abundant on the lower eastern flanks of the Rincon Mountains in the Happy Valley area. Early in spring the waxy, urn-shaped blossoms, the leathery, glossy, evergreen leaves, and the typical grotesquely crooked, red-barked limbs, make manzanita one of the most attractive shrubs of the chaparral.

AlthoughSKUNKBUSHis a close relative of poison ivy and sumac, its aromatic foliage is harmless. Growing in compact thickets, skunkbush provides food and cover for birds and other small animals. Inconspicuous yellow flowers appear from March to June, and are followed by berrylike fruits which are dull red when mature.

As you follow the trail higher, occasionalMEXICAN PINYON PINESandALLIGATOR JUNIPERSappear. Gradually these evergreens become more abundant, mingling with the oaks to form a pigmy oak-pine-juniper forest. Clumps ofMOUNTAIN-MAHOGANYare noticeable, their feathery seed “tails” gleaming in the sunshine.

Pinyons are among the commonest and most widespread trees of the middle elevations throughout the Southwest. The Mexican pinyon, which is the species growing abundantly in the Tanque Verde-Rincon upland, may be recognized by the fact that its foliage is in clusters of three needles to the bundle. Its cones require nearly 2 years to mature and contain hard-shelled seeds or nuts which are a source of food for many birds and mammals. These pines are usually shrubby, rarely more than 15 to 25 feet high, with horizontal, twisted, low-growing limbs. Intermingled with the pinyons are alligator junipers, often mistakenly called cedars. Those in the monument are conspicuous because theirplaty bark forms an attractive pattern resembling the squarish-scaled skin of alligators. The berrylike cones are soft and mealy, and are eaten by many kinds of wild animals.

Although the oak-pine woodland supports a heavy stand of shrubby trees over much of the terrain, there are numerous open glades and grassy hillsides. In addition to some of the aforementioned grasses,BLUEGRASS,BULLGRASS, andPLAINS LIVEGRASSprovide ground cover in this belt. Following summer showers, many flowering herbs brighten the open slopes. Yellow to orange petals ofPUCCOON, and the white to lavender-and-rose blossoms ofMOCK-PENNYROYALandHOUSTONIAare among those seen along the trailside.

Just as grassland merges with oak woodland and chaparral, and these with oak-pine woodland, so you will notice, as you climb steadily higher, that these woodlands gradually mingle with the open pine forests that cover much of the Rincon Mountains above 6,000 feet.PONDEROSA PINEis the “big tree” of the Rincons, usually growing in clear, open stands. Through its high canopy of spreading branches, sunlight mottles the shaded forest floor. Its presence indicates still cooler and wetter conditions than those below. Here you will need blankets at night, though summer days are warm.

Except for grasses such asPINE DROPSEED,SCREWLEAF MUHLY, andMOUNTAIN MUHLY, ground cover is scarce. In tree-glades or on old burns, however, intermediate-type shrubs (such asBUCKBUSH) and various herbs have established themselves. Some herbs develop into patches of colorful flowers in summer and autumn. Common flowering plants found among the pines areCOLOGANIA;PEAVINE, with its large and showy, white, sweetpea-like blossoms throughout the summer; lupines;DOGBANE; and the familiar whiteWESTERN YARROW. Here, too, may be foundGROUNDSEL,ASTER,FLEABANE, and others, often brightened by the presence of butterflies and other insects seeking nectar and pollen. Most of these forest flowers bloom in late summer or autumn, when plants in the desert, far below, are drab and dormant.

Throughout the pine forests, numerous small canyons and rocky outcrops favor the development of thickets of oak and locust, frequently growing together.GAMBEL’S OAK, a leaf-shedding white oak, ranges in size from a small shrub to a handsome tree. It has broad, deeply lobed leaves which provide browse for deer. Its acorns are consumed by deer, rodents, and birds, including wild turkeys. TheNEW MEXICAN LOCUSTalso is browsed by deer. Rarely reaching tree size, this species is an attractive vegetative cover because of its odd-pinnate leaves and large clusters of purplish-pink flowers that appear in May and June. Locusts sprout freelyfrom roots and form expanding thickets which encroach upon oak clumps. They provide a valuable network of soil-holding roots, important in retarding erosion. The best stands occur along the east slopes of the Rincons.

Relatively few in number, compared with the stands of the dominant ponderosa pine, the smallerCHIHUAHUA PINEgrows on lower dry slopes and benches. Its needles are shorter than those of the ponderosa pine, and its cones are conspicuously persistent, remaining on the tree for several years. This Mexican species invades the United States in the mountain ranges of southern Arizona and southwestern New Mexico. In the monument it is found mostly in the transition areas between oak-pine woodland and ponderosa pine forest.

The Rincon Mountains are not high enough to provide a fir-forest habitat except in a few favorable locations. On the highest parts of the Rincons, ponderosa pines dominate in the warmer, exposed locations, but whitebarkedQUAKING ASPENSgrow in pure stands on cooler slopes and withDOUGLAS-FIRSon the north side of Rincon Peak. West of Spud Rock are abundant small groves ofMEXICAN WHITE PINE.

A cone-bearing tree growing with Douglas-fir—exclusively on higher northern and northeastern slopes of Mica Mountain—is theWHITE FIR. Flattened, gray-green needles curving upward from the branches, and large, green cones growing upright on limbs near the tops of the trees identify this beautiful evergreen. On open stands, limbs of even the large trees grow from the trunk almost down to the ground. The bark is gray or ash-colored.

BRACKENforms a green ground cover in heavy stands of pine and fir. This fern grows 3 feet tall over much of the forested Rincon highland. Among the shrubs found on the mountaintop is theSNOWBERRY, whose leaves are browsed by deer and whose berries are eaten by birds and chipmunks.

A spring, a small mountain stream, and a meadow near Manning Camp complete the picture of the higher elevations in the monument. In this bit of meadowland are foundBOXELDER,NEW MEXICAN ALDER,CINQUEFOIL,CHOKECHERRY,GOLDENROD,ORANGE SNEEZEWEED,MARIGOLD,WILLOW, and a number of other shrubs, grasses, and herbs characteristic of the high mountain meadows of the Southwest.

Jerusalem cricket (of a different family from the true crickets) has legs adapted for tunneling in sand.

Just as plants depend for their existence on soil, water, and sunlight, so animals, including man, depend on plants. For green plants are the basic food producers in nature, manufacturing carbohydrates, proteins, and other essential compounds from minerals, air, and water, with the help of chlorophyll and the sun’s energy. Animals get their food either by eating green plants or by eating animals that have eaten plants. Microscopic decomposers complete this food chain, breaking down dead plants and animals into substances that once again can be used by plants. Since each link in the chain depends on the other links, it’s not hard to see that a change in one will cause a change in the others. And because animals depend on plants for cover as well as for food, their fortunes are doubly tied to the welfare of plants.

Animals and plants share some of the same basic problems—particularly, how to stay within tolerable temperature limits, and how to maintain an adequate supply of water. Plants solve these problems mostly by structural adaptations, animals mostly by behavioral. In the desert, for instance, cold-blooded animals such as snakes and lizards (which have no internal control over body temperature) crawl underground or into shade during the midday heat of summer, and come out to hunt food during the cooler hours. Birds and mammals cool themselves through evaporation of water from their bodies. This makes water conservation doubly critical for them; they too handle it by staying in the shade or going underground during hot times. Desert animals get much of their water from the plants and animals they eat, but some species, such as mule deer and Gambel’s quail, require large amounts of drinking water as well.

Cold weather poses another problem. Most reptiles and some mammals solve this one by hibernating underground or in rock dens, where temperatures remain moderate throughout the year. Many birds and some mammals migrate to areas where temperatures are warmer and food is more abundant, which may mean going farther south or simply moving down the mountainsides. And insects can survive in a dormant form, as eggs or pupae, though many species remain active during the temperate Sonoran winters.

If you want to see animals, then, go where the vegetation is thickest and most varied, and go when temperatures are moderate. During warm seasons in the desert, this means that walking the washes early or late in the day will give you the best chances for seeing wildlife. Coveys of Gambel’s quail explode into the air, peccaries snort through the underbrush, butterflies festoon flowering shrubs, and coyotes stealthily hunt.

Insects are generally not bothered by excessive heat, and many species are active during the hottest hours. This is especially true when the plant blossoming season is at its height. Flowers of the mesquite, paloverde, catclaw, saguaro, and other desert plants are “alive” all through the day, as many species of insects seek nectar and pollen or prey on other insects attracted to the blossoms. Insects are fed upon by various species of birds; flycatchers flock to parts of the desert where nectar-yielding flowers are numerous. Because of the absence of extreme cold, the desert climate enables insects to be active throughout much of the year and to support a considerable bird population.

Despite its fearsome appearance and reputation, you have nothing to fear from the tarantula.

Insects play a far more important role in the plant and animal life of the desert than is usually realized. Many desert flowers must be insect pollinated to produce viable seeds. Birds of many kinds depend upon insects for food, and even the seed-eating birds, during the nesting season, rely upon insects to provide the enormous quantities of food and moisture required by their fast-growing nestlings. Many other desert creatures, including certainsnakes and lizards and some spiders, depend upon insects for food. The body juices of the insects provide the all-important moisture—which these creatures can get from no other source. Bats, too, are insect eaters, spending the hours of darkness in seemingly aimless and erratic flight while foraging for moths and other night-flying insects that visit the light-colored blossoms of night-blooming plants.

Some species of insects may become so numerous that they threaten the very life of the plants on which they live. Pine bark beetles annually damage or kill numbers of pinyons and ponderosas in the Rincon Mountains, but have been kept sufficiently under control by their natural enemies so that their ravages have not reached epidemic proportions.

Among the common spectacular insects is theTARANTULA HAWK, a large blue-black, red-winged wasp that preys on large spiders. Temporarily paralyzing the spider with its sting, the wasp lays a single egg on its victim, thereby assuring an abundance of living food for its young. ThePRAYING MANTISis another large insect, usually green and inconspicuous among the foliage of desert plants, which it frequents in search of small insects. Ants of many species are active almost everywhere in the desert, harvesting seeds of various plants. Some species construct mazes of underground nest tunnels and deposit the excavated materials on the surface, forming conical, sometimes, craterlike, anthills.

The small desert hairy scorpion is the only scorpion in the monument that is dangerous to humans.

Along with the insects, other arthropods (jointed-leg creatures with exoskeletons) find their home in the desert. The arachnids (eight-legged arthropods) include spiders and scorpions. Of theformer, theNORTH AMERICAN TARANTULASare famous for their large size and formidable appearance, which have given them the wholly undeserved reputation of being dangerous to humans. The really dangerous creatures are theSCORPIONS, whose long, flexible tails bear a poisonous stinger at the tip. Several species are found in the monument; but only the small, straw-colored scorpion has venom known to have been fatal to humans. The other scorpions found in the area can inflict painful stings, but with only localized and rarely serious effects.

The Colorado River toad is exceeded in size among U.S. toads only by the giant toad of south Texas (and Mexico).

As might be expected, amphibians are scarce in the monument because of lack of permanent water. The few springs and seeps, however, furnish excellent breeding places for several species of amphibians. Best known among these are theRED-SPOTTED TOAD,LEOPARD FROG, andCANYON TREEFROG, the latter common near Manning Camp. A spectacular desert amphibian and the second largest toad in the United States, is the hugeCOLORADO RIVER TOAD, sometimes found near residences in the evening when outdoor lights attract swarms of insects.

Except for small lizards, reptiles are not much in evidence in the monument. Nevertheless, they are present and are important inthe various plant-and-animal communities in which they live. Almost all lizards are insectivorous, and along with birds and other insect-eaters help to keep the number of insects within bounds. A notable exception is theGILA(HEE-lah)MONSTER, (Seeappendixfor scientific names of reptiles) largest of the lizards found in the United States. (It is one of the world’s two poisonous lizards, and the only one found in this country.) The gila monster is especially fond of bird eggs, and also eats nestlings and small rodents, obtaining necessary moisture from their body juices. These food habits are quite similar to those of the several species of snakes found in the monument, the majority of which are perfectly harmless to humans.

The short-horned lizard, more cold-tolerant than the desert horned lizard, ranges from the foothills into the mountain forests of Saguaro.

Just as the lizards help to control the insect population, the snakes are important in preventing the buildup of large numbers of rodents that would result in widespread damage to vegetation. Visitors to the monument rarely have the opportunity to observe snakes, since they are in hibernation during winter and remain in the shade or in underground burrows during the hot part of each summer day. Perhaps those most frequently seen are theGOPHER SNAKEand theCOACHWHIP. Many desert snakes hunt only at night; others that are normally active during days of moderate temperatures become night hunters during hot weather. Although they are not abundant, there are several kinds of rattlesnakes in the monument, the commonest desert species being theWESTERN DIAMONDBACKandMOHAVE RATTLESNAKES. Except for the small, very rare, and secretiveARIZONA CORAL SNAKE, rattlesnakes are the only poisonous snakes in the monument. Snakes, like other living things in the national monument, are protected by law.

Don’t be surprised while following a desert footpath to come upon a plodding tortoise. This bona fide desert dweller, theDESERT TORTOISE, is a vegetarian, feeding on cactus, grass, and other low-growing plants.

Because of its great variety of habitats, ranging from luxurious desert vegetation to deep mountain forests, Saguaro National Monument provides food and shelter for many species of birds. Some of these reside all year within a single zone, while others move upward in summer, returning to the desert when the mountaintops are covered with snow. Other species pass through the monument in spring and autumn in their annual migrations between Latin America and summer nesting grounds in northern United States or Canada. The following species are those you are most likely to see.

The Mojave rattlesnake prefers desert, grassland, and open brushland to densely vegetated areas.

A common year-round desert resident is theCURVE-BILLED THRASHER, noticeable, noisy, and about the size of a robin. Theseenergetic inhabitants of the cactus forests nest in mesquite clumps and cholla thickets. Their diet—they feed on insects and succulent fruits—makes them comparatively independent of water. The thrashers are delightful songsters. TheCACTUS WREN, looking somewhat like a small thrasher, is even noisier. It protects its nest by building in a cactus. This wren lives largely on a diet of insects, but about 17 percent of its food is seeds and fruits. One of the most attractive of the ground birds is theGAMBEL’S QUAIL. Many coveys are found throughout the desert within close range of water. In winter, Gambel’s quail feed mainly on seeds, berries, and plant shoots; in summer they augment this diet with ants, grasshoppers, and other insects. TheROADRUNNER, ungainly clown of the desert, is frequently seen by visitors as it scuttles through the underbrush along the margins of sandy washes. Not particular as to food, it is sometimes seen with the tail of a lizard protruding from its beak, and it is known to eat insects and spiders, snakes, young rodents, small birds, seeds, and fruits. Quite capable of flight, the roadrunner prefers to trust to its legs and the security of thickets, but will take to its wings if pursued in the open.

You may mistake the curve-billed thrasher’s call, “whit-wheet,” for a human whistle of attention.

Two members of the woodpecker family closely associated with the saguaro cactus are theGILA WOODPECKERandGILDED FLICKER. Called carpenter birds because they drill nest holes or pockets inthe saguaro stems, both species are of particular interest because of their limited range and specialized habitat. Two other desert birds, sufficiently similar to be confused, are the red, black-facedCARDINALand the gray-and-redPYRRHULOXIA, both of which have crests. Look for these species in the shrubs along washes. Several kinds of doves are found in the desert, including the commonMOURNING DOVEand theWHITE-WINGED DOVE. Mourning doves are all-year residents, while the large white-wings drift in from Mexico in May, remaining long enough to raise families and join other animals in harvesting fruits of the saguaro.

The gilded flicker drills its nest hole in the saguaro.

Seen and heard in the desert all year, the canary-voicedHOUSE FINCHraises its family among cholla and mesquite thickets. The tinkling song of theROCK WRENis a familiar sound in the desert in winter. These gray ground dwellers go farther north or to higher elevations to nest.

ThePHAINOPEPLAis one of the most noticeable of the desert birds because of its silky crest, glossy black plumage, and habit of perching on the topmost branch of a tree while indulging in flutelike song. A permanent resident of the monument, subsisting on mistletoe berries and other vegetable matter in winter, it has a diet of insects, principally ants, during the rest of the year. Flycatchers are especially abundant and conspicuous during springand early summer when the blossoms of trees, shrubs, and the larger cactuses attract swarms of insects. Among these birds areSAY’S PHOEBEandASH-THROATED FLYCATCHER. TheLESSER NIGHTHAWKlives on a diet of insects, which it catches while on the wing. It is especially noticeable from May to September as it skims the tops of the tallest saguaros in the dusk of evening. The lesser nighthawk also ranges up to the oak woodlands.

The white-winged dove’s interest in the saguaro is in the nectar and fruit.

Predators are an integral part of the bird population, one of the smallest and most active being theLOGGERHEAD SHRIKE. This black-and-gray bird gorges itself on beetles and grasshoppers when insects are abundant, turning to lizards, rodents, and small birds at other times. It has the unusual habit of impaling its prey on thorns for future use. TheRED-TAILED HAWKis the commonest of the large soaring hawks, which live mainly on rodents and reptiles. It builds its large stick nest in the forks of saguaro arms. Like the shrike and theSPARROW HAWK, the red-tailed hawk is found in grasslands, chaparral, and woodlands as well as in the desert. Because of their nocturnal habits, owls are not often seen by visitors, but they are abundant in the monument. In addition to theGREAT HORNED OWL, which like the red-tailed hawk feeds principally on rodents and builds cumbersome nests in saguaro branches, theSCREECH OWLand the tinyELF OWLare numerousin the cactus community. Screech and elf owls make use of abandoned woodpecker holes in saguaros, not so much for nesting as for dark and comfortable hiding places during daylight hours; they emerge after sunset to hunt insects and small rodents. Best known of the carrion eaters, theTURKEY VULTUREis rarely seen on the ground, but is a common sight, singly or in groups, circling high in the sky.

The red-tailed hawk builds its nest in the fork of a saguaro and by day ranges over the entire monument in search of prey.

The oak-pine-juniper woodland has its set of birds too. One of the noisiest, most quarrelsome, and most mischievous is theMEXICAN JAY, a permanent resident. In summer, it shares this habitat with the night-flying poor-will, which closely resembles the nighthawk but lacks the white wing patches. Shy, secretive, and protectively colored, this bird is rarely seen, but its plaintive call is a familiar twilight sound at the middle elevations of the mountains. Here, too, is found the strikingly patternedHARLEQUIN QUAIL, which waits until you are almost upon it before flushing. TheRUFOUS-SIDED TOWHEEprefers brushy slopes and canyons, where it trills its monotonous song from the branch ofa skunkbush or scratches noisily and industriously among the fallen leaves beneath an oak. And anywhere from the oak-pine woodland to the top of the Rincons, you are likely to startle the largeBAND-TAILED PIGEONfrom its perch.

The pine and fir forests of the higher Rincons are rich in bird life in summer, but only a few species remain the year around. Among the latter is theSTELLER’S JAY, which includes insects in its summer diet but feeds mainly on acorns and other vegetable material in winter. TheMOUNTAIN CHICKADEEis busy among the branches of the large pines and firs even when snow lies deep on the ground.PIGMY NUTHATCHES—tiny, constantly twittering insect-eaters—also remain all year.

The great horned owl, a nocturnal counterpart of the red-tailed hawk, nests in the saguaro and feeds primarily on rodents.

Steller’s jay lives year-round in the pine and fir forests of the higher Rincons.

In summer, when insects are plentiful, the mountain forests are alive with birds. TheMEXICAN JUNCO, which winters at lower elevations, hides its nest in grass clumps among the firs and aspens. Hummingbirds of several species pause on vibrating wings to suck nectar from blossoms in the meadow at Manning Camp. Brightlycolored summer visitors such as theHEPATIC TANAGERand thePAINTED REDSTARTsearch for insects among the pine boughs or flash in the sunlight as they flutter across open glades in the forest. The mountaintops, too, have their predators; theCOOPER’S HAWK, which nests in wooded canyons, is large enough to lift a pigeon or rabbit, but generally preys on rodents and smaller birds. The largest bird known to inhabit the Rincon Mountains is theTURKEY, which nests and raises its young among the firs and aspens. It descends in winter to the oak-pine woodlands, where it feeds on pinyon nuts, acorns, and grass seeds.

The most frequently seen mammals in the monument are rodents and members of the hare clan. Among the latter group are two rabbits. TheDESERT COTTONTAILis common in the lower levels of the desert, and theEASTERN COTTONTAILinhabits the mountains to 8,600 feet. Adaptable to a wide range of environmental conditions, these animals augment the water they obtain from springs with moisture derived from sap. There are two species ofJACKRABBITS(actually hares) in the monument. They remain at the lower levels, where they are a common sight amid the cactuses. Unlike rabbits, which are born naked, blind, and helpless, hares are born with fur, open eyes, and the ability to move about.

The Yuma (or gray-tailed) antelope ground squirrel, a chipmunk-like rodent of the desert and grassland.

In the monument, the cliff chipmunk prefers the oak-pine woodland and the coniferous forest.

Among the monument rodents the largest are thePORCUPINES.Though rarely seen, they leave characteristic scars on pinyons and ponderosa pines, recording their feeding habits at higher elevations. They are also active in the chaparral belt, and an individual occasionally wanders down into the desert where it eats mesquite beans and samples the bark of ocotillos and other shrubs and trees.

Several species of ground squirrels are abundant. At the lower levels, especially among creosotebushes, theROUNDTAIL GROUND SQUIRRELfinds suitable living conditions, while theYUMA ANTELOPE GROUND SQUIRRELranges from the cactus forests into grassland. At this elevation and upward through the pinyons and junipers, theROCK SQUIRRELmakes its burrows in rocky ledges and brushy canyons.CLIFF CHIPMUNKSenliven the oak-pine woodland and higher forests with their quick movements and cheerful chatter.

KANGAROO RATShoneycomb the soil from the cactus forests up to the oak-pine belt. Remaining underground during the day, they are frequently seen at night. These animals do not require free water; they obtain adequate moisture from a chemical process within the body during the digestion of food, which is mostly dry seeds.WOODRATS, famous in song and story as pack rats or trade rats because of their habit of carrying away objects of human use and leaving something else in their place, are found throughout the monument at all elevations. Look for their stick nests among the pads of prickly pear, a favorite food.

Other rodents common in the monument include theCACTUS MOUSE,GRASSHOPPER MOUSE,DEER MOUSE, andVALLEY POCKET GOPHER.

The four species of kangaroo rats found in Saguaro look too much alike to be distinguished in the field.

Mule deer.

Among the larger mammals in the monument are two species of deer. TheMULE DEERsubsists in winter on cactus fruits, ephemerals, and other desert vegetation. In summer they find abundant browse in the higher oak woodland. The forested areas along the crest of the Rincons support a population of the smallerWHITETAIL DEER. These graceful animals browse on aspen, buckbrush, and other shrubs and small trees. They are particularly fond of acorns. When snow flies some descend to the protective cover of the oak-pine woodlands and chaparral.

PECCARIES, characteristic of southwestern deserts, usually travel in herds of from three to as many as 50 animals. They wander through the groves of mesquite along desert washes, and root among beds of pricklypear. Pricklypear pads are their chief food; they are said to feed upon cactus fruits in summer and autumn. In addition to the moisture obtained from succulent stems and fruits, peccaries require considerable water, hence they frequent springs and seeps. Small bands of these animals occasionally visit the waterhole near the visitor center, where they are excitedly watched by visitors fortunate enough to be in the lobby at the time.

Saguaro National Monument also has a large number of predatory animals. Many of these, popularly believed to be exclusively meat-eaters, actually also eat much vegetable matter. The predators—an exciting part of the monument’s fauna—play an important role in preventing overpopulation of the prolific rodents.

Chief among predators is theCOYOTE, which ranges throughout the monument. In winter, coyotes are found principally below6,000 feet, where hunting is easier and where rodents remain longer out of hibernation. They are also known to roam the forested heights of the Rincons and Tanque Verde Ridge. Studies of coyotes in the monument made by biologist Lowell Sumner in January 1951 showed that their winter diet consisted of about 78 percent fruits and seeds, 11 percent small rodents, 7 percent deer, 4 percent birds, reptiles, insects, and carrion, and 1 percent debris. The coyote is one of the principal wild creatures associated with the history of the West, and its continuing presence in the monument brings a thrill of pleasure to visitors who hear the voices of the pack during the calm of evening, or catch a glimpse of one of these gray canines trotting through open stands of saguaros.BOBCATS, ranging over much the same territory as coyotes, subsist principally on rodents, birds, and insects. Because of their secretive habits, they are seldom seen.

Collared peccary, or javelina.

TheGRAY FOXis another fairly common inhabitant of the cactus desert and higher brushlands, and is also known to roam the forested uplands. It is usually seen at night. Rodents are its principal source of food, but it also preys on birds and reptiles and eats much vegetable matter. The smaller and rather rareKIT FOX, restricted mostly to the desert, is also a night hunter. Kangaroo rats are a favorite item in the kit fox diet, but these small predators also eat grasshoppers and other insects.

Skunks, members of the weasel family, are relatively common in the monument, and several species inhabit areas where water is available. They are usually active at night. TheHOGNOSE SKUNKis a desert dweller recognizable by its solid-white back. It rootsfor insect larvae and eats cactus fruits, bird eggs, and nestlings. TheSTRIPED SKUNKranges throughout the monument; theSPOTTED SKUNKis found at all elevations, usually among rocks. Insects, rodents, and fruits are its main food.

Another member of the weasel family, theBADGER, is occasionally seen in the desert although it is by no means limited to that habitat. The badger feeds mainly on rodents, which it digs from burrows with its strong forelegs and heavy claws.

TheRACCOON, longer-legged than the badger, is readily recognized by its gray fur, black mask, and ambling gait. It inhabits brushy canyons having permanent water, and sometimes wanders up into the pine belt in summer. Amphibians, scarce as they are, and other water creatures are among the preferred foods of raccoons; but they also eat small rodents and plant food, including berries, acorns, and other fruits.

Badger.

TheRINGTAIL, a smaller relative of the raccoon, is somewhat similar in habitat preference and nocturnal habits. Its flattened, bushy tail, acting as a balancer, helps this short-legged, agile animal in leaping from point to point on the steep rocky surfaces it seems to favor. It sometimes takes up residence in little-used or abandoned buildings, where small rodents, its principalsource of food, are usually abundant. About the size of a house cat, it has large eyes and ears and alternating dark and light bands on its tail.

A tropical animal that seems to be extending its range northward, theCOATI(or coatimundi) is often seen in the forests of the Rincons. With long snout and long, banded tail, it looks something like an elongated raccoon, to which it too is related. These omnivorous animals travel in bands, rooting among leaves for insects and whatever else they can find.

Coati, or coatimundi.

Desert vegetation near Red Hill, Tucson Mountain Section.

Natural landscapes may appear unchanging, but this is illusion. Within the apparent constancy, daily and seasonal cycles, fluctuations in numbers, and long-term change are the rule.

Daily cycles are obvious to those who are about at the edges of the day. Take 24 summer hours in the cactus forest of Saguaro National Monument. When the first light comes over the mountains, curve-billed thrashers and cactus wrens sing noisily among the chollas. Other birds soon join in. The early morning walker is likely to hear peccaries grunting in the mesquites along a wash, or see mule deer staring at him, frozen like statues before sudden flight to a sheltering thicket.

At midday, the scene is quiet. Nothing stirs under the baking sun except perhaps a vulture, soaring on the hot air currents. The desert creatures have not gone—they are in the shade of bushes or underground. Even some of the plants are “taking a siesta,” having folded their leaves or closed their leaf pores.

Soon after sundown the desert comes to life again. The birds give a subdued version of their morning’s vocal performance. Tarantulas begin their slow, stately walk over the ground searching for prey or mates. Coyotes stretch and howl—a prelude to the evening’s hunt. As night falls, rattlesnakes emerge from their cool retreats to search out kangaroo rats, which in great numbers are scrutinizing the sand for seeds. And through the night, creatures of many other kinds hunt food to last them through another broiling day.

The rhythmic patterns of the daily cycle are paralleled on a larger scale through the year—seasons of activity follow seasons of quiet. In the desert, rain or lack of rain marks the changes, though gradually rising or falling temperature adds its impact.

The gentle rains of winter prepare the way for the year’s greatest burst of activity. By March, spring flowers are blooming and birds are starting to nest. Snakes begin to come out of hibernation. April and May see the apex of spring activity, as insects swarm around the flowering plants, and birds take advantage of this proliferation of food to raise their young. The desert now isyellow with the blossoms of paloverde, mesquite, acacia, and brittlebush.

But April also marks the beginning of a drought that intensifies through May and June, making these last 2 months the year’s parching crucible in which reproductive ability is tested. If winter rains have been meager, the heat and drought of May and June can kill all the young of many birds. Some birds, such as Gambel’s quail, may not even attempt to nest in a dry year. Conditions may be so harsh at this season that some mammals, such as the pocket mouse, close up shop completely, sleeping the days away underground.

Relief comes with the rains of July and August. Now the summer annuals spring magically from the ground, perennials put forth new leaves, and saguaros do all their growing for the year. This summer burst of plant growth is accompanied by a new hatching of insects, which allows a few more birds to nest, and along with the new vegetation supports a larger pyramid of animal life generally. Among the new animals that reappear are toads, which now emerge from their long sleep in the soil to mate and lay eggs in the pools formed by summer rains.

When the last torrential rain of August or September falls, a new dip in the yearly cycle of activity begins. This one is not so deep, not so trying, as the drought of early summer, but it too is a time of relative quiet. Roundtail squirrels go underground to sleep until cooler weather comes. Now the migrating birds slip through, hardly noticed among the mesquites and paloverdes. Butterflies lay their eggs, in preparation for a new generation beyond the winter. Signaling the last phase in the yearly cycle, wet canyons turn yellow and brown as cottonwoods, willows, and sycamores present a pale version of the spectacular foliage displays seen in the East.

While these daily and seasonal cycles are following their well-known courses, each species of plant and animal is undergoing its own fluctuations, in a constant struggle that generally goes unnoticed. For the balance of nature is not a static one, but more like the rocking of a seesaw on its fulcrum. The population of a species goes up one year, down another—depending on the weather, the food supply, predators, competitors, and a thousand interactions that reverberate through the community in which it lives. The numbers of some species, like the Gambel’s quail, fluctuate wildly from year to year, while those of others, such as the harvester ant, remain quite stable. But the oscillations of the seesaw, big and little, average out from year to year so that the species maintains itself in the community. The other members are going through the same thing, in a system of checks andbalances that over the short run keeps the whole community nearly constant.

But over decades, centuries, or longer, the fulcrum of the seesaw moves: the larger environment changes, and the community and its constituent plants and animals must change with it or perish. Such changes may be climatic, as we saw with the formation of the Southwestern deserts; or it may be geologic, as with the rising and partial disintegration of the Rincon Mountains. The efforts of plant and animal species to meet such changes constitute in large part the story of evolution, for new environments spawn newly evolved forms of life. Evidence of such evolution we have seen in the plants of the Sonoran Desert, notably the giant saguaro cactus, whose prickly ancestor lived in the West Indies only 20,000 years ago.

Thus nature is ever-changing; and the inexorable rule for all living things is, “adapt or perish.” Before technological man enters the scene, the slow evolutionary process can keep pace with the changing environments, though here and there a species is dropped by the wayside. Generally, communities of living things reach new equilibria without serious disruption.

But what happens when man, with his machines and his passion for progress, institutes changes of a speed and kind and on a scale drastically different from those brought about by earthquakes, storms, shifting climates, and other natural phenomena? What happens to the living things that have adapted to the harsh desert environment when that environment is drastically altered?

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