Saguaro

“ The ecological importance of the Saguaro to animals is better known. Two species of Woodpeckers, the Gila Woodpecker and the Gilded Flicker, drill deep holes into the plant and fashion nests in the cool interior. Actually this causes little damage to the Saguaro, which soon forms a thick scar tissue around the walls of the excavation, sealing it away from the rest of the plant. In succeeding years these nests may be taken over by Elf Owls, Sparrow Hawks, Flycatchers, or Purple Martins. Larger birds build their nests among the branches of the Saguaro. ”

“ The fauna of each community is made up of animals adapted to the climatic conditions and the available food, cover, and water. In Saguaro, some animals, such as the desert kangaroo rat and the cactus wren, are restricted by their life requirements to a narrow belt; others, such as the gray fox and great horned owl, are more adaptable and live in all the major plant communities. ”

“ Saving the saguaros is inevitably tied to the problem of enhancing the quality of life and reversing the degradation of the environment—not only in Tucson but throughout the Southwest.
There is no time to waste. Only concerted effort by scientists, resource managers, and the community can assure that our grandchildren will be able to visit a Saguaro National Monument where coyotes howl under the moon, peccaries snort through the washes, and giant cactuses lift bristly green arms into a blue sky. ”

“ 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 the LOGGERHEAD 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. The RED-TAILED HAWK is the commonest of the large soaring hawks, which live mainly on rodents and reptiles. ”

“ The most striking aspect of the plant communities within the monument are the abundant saguaro cactus forests. The saguaro is a signature plant of the Sonoran Desert. Individual saguaro plants are indeed magnificent, but a forest of these plants, together with the wide variety of trees, shrubs, and herbaceous plants that make up the forest community, is an impressive site to behold. The saguaro cactus forests within the monument are a national treasure, rivaling those within the Saguaro National Park. ”

“ The thinning and final disappearance of saguaros along the trailside, although mesquite and ocotillos seem almost as numerous as on the floor of the desert, indicate that you are entering a slightly cooler, wetter environment. An occasional MEXICAN BLUE OAK or ARIZONA ROSEWOOD appears among the mesquites along the washes. The grasses that increasingly cover the ground as you climb include HAIRY, SIDEOATS, and SPRUCETOP GRAMA ”

“ Although billions of saguaro seeds are produced yearly in the extensive stands of the monument, only a very few find favorable locations for germination and growth. Trees, rocks, dead limbs, pebbles—anything that reduces evaporation in the immediate vicinity of the seed—improve the chance of germination. These kinds of shelter not only provide the necessary moisture conditions, but also hide the seed from armies of ants, rodents, and other animals searching for food. ”

“ In reality they are compromises—beautiful, wild, but still bearing the marks of human occupation. In Saguaro, as we have seen, fire control has produced a forest different from that known to the Indians who once lived here; grazing has depleted the ground cover; and hunting has removed the desert bighorn from its rocky haunts. In these days of burgeoning population, when human influence is affecting every natural landscape, environmental management becomes necessary to approach the ideal of naturalness. ”

“ Man’s killing of predators, their natural enemies, further encouraged proliferation of these rodents, which some people say are especially destructive of saguaro seeds and young plants. Whatever the effect these rodents have on the saguaros, the removal of ground cover intensified erosion and reduced the chances for the seeds to germinate and grow. And certainly the cutting of desert trees removed shade that would have benefited young saguaros. ”

“ 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. ”

“ The fruit is not cooked, and never preserved save in the noisome way of nature, and is rarely transported in quantities or over distances of industrial importance; yet the product may have some connection with the basketry of the tribe. The devices for collecting the fruits, especially from the lofty saguaro and saguesa, are mere improvisations of harpoon shafts, paloblanco branches, or chance cane-stalks carried primarily for arrow-making or balsa construction. ”

“ This book is a simple account of the natural history of Saguaro National Monument. It is intended to help you understand the relationships between land, climate, plants, wild animals, and man in the environment of a hot desert. While it includes brief profiles of many representative species, it is not intended to serve as a guide to the monument. It does indicate where the several distinctive natural communities exist, and when and where to look for certain plants and animals. ”

“ All of the cacti of the region yield tunas in considerable quantity. The pitahaya is perhaps the most abundant producer, and its name is often given to the fruit; the huge saguaro affords an enormous annual yield, and the still more gigantic saguesa is even more prolific, especially in its immense forests along the eastern base of Sierra Seri; the cina adds materially to the aggregate product, while the nopal, or common prickly pear, contributes a quota acquiring importance from the facility with which it may be harvested. ”

“ Habitat: This uncommon small owl inhabits the saguaro cactus in Sonoran deserts and wooded river bottoms near the Mexican border.
Nest: Nests are in abandoned woodpecker holes in mesquite, cottonwood, and saguaro cactus. Nest heights range from 10 to 40 feet above ground (Bent 1938, Karalus and Eckert 1974) .
Food: The diet of the ferruginous owl consists primarily of small birds; however, insects, small mammals, invertebrates, reptiles, and amphibians are occasionally eaten (Karalus and Eckert 1974) . ”

“ 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. ”

“ Some were tall, like trees. Others were round, hugging the ground and looking like brownish cabbages. There were some that looked like toadstools, except that they were branched and had several caps. Nearly all the plants were branched, and a few had flowers ranging from delicate pink to deep purple. None seemed to have leaves.
The largest looked like the Giant Cactus—the saguaro—of Arizona, although it was not spined. ”

“ 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. ”

“ The roots that serve this living storage tank are no less remarkable. The tap root is small and acts as little more than a pad to support the great weight of the plant. The radial roots are heavy and of great length. They radiate out from the base of the Saguaro, usually no more than a foot below the surface of the ground, but often to a distance equal to the height of the plant. They serve the double purpose of gathering food and moisture, and of holding the great bulk of the trunk upright against the fierce desert storms. ”

“ The poisonous insects and reptiles are not at this time warmed up to full activity, while many peculiar plants are just coming into bloom.
Let us study some of the strange forms growing thickly over the rocky slopes and sandy plains. There are miles of forest, but not such a forest as we are accustomed to see. Tall, fluted columns of the giant cactus (saguaro) , with rows of sharp spines, reach upward to a height of from twenty to fifty feet. ”

“ When 9 years old, they are about 15 centimeters high. After about 75 years, the cacti are tall and develop their first branches. When fully grown, saguaro are 15 meters tall and weigh as much as 10 tons. ”

“ It eats insects, spiders, lizards, small snakes and mice. Rattlesnakes sometimes are killed by Roadrunners.
Whitewinged Dove—Large numbers of these birds may be seen in the Cactus Forest when the Saguaro fruits are ripe.
Gambel Quail—A common desert dweller that may be observed at any season of the year. It nests on the ground.
Arizona Rock Squirrel—Distinguished from the Gray Squirrels by their less bushy tail and mottled coat. They are ground dwellers, but can climb trees if necessary. ”

“ The root of the ocotillo plant supplies the red. The pulpy sap of the saguaro (giant) cactus gives the blue. Brown and yellow are made from the first layer of skin under the bark of the palo verde tree, and green comes from sage leaves while mesquite beans make the thick black. The degree of boiling gives the shades desired.
The preservation of San Xavier del Bac is a worthy gesture in enabling increasing thousands to see intact this magnificent example of early mission architecture.
33 Bibliography ”

“ Photographers will note that several trails have been laid out for their convenience. These lead to particularly fine specimens and groups of Saguaros, but have not been developed as permanent trails. They are merely guides to the better photographic locations. ”

“ Flickers, or "Yellowhammers," use dead trees as a rule, but sometimes make use of a living tree by digging the nest out of the dead wood where a knot hole offers a convenient opening. The only place I have ever known them regularly to nest in living trees is in the deserts of Arizona, where the saguaro or "tree cactus" is about the only tree large enough to be employed for such a purpose. In the {35} Northern States Flickers sometimes chisel holes through the weatherboarding of ice-houses and make cavities for their eggs in the tightly packed sawdust within. ”

“ At this elevation and upward through the pinyons and junipers, the ROCK SQUIRREL makes its burrows in rocky ledges and brushy canyons. CLIFF CHIPMUNKS enliven the oak-pine woodland and higher forests with their quick movements and cheerful chatter.
KANGAROO RATS honeycomb 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. ”

“ 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 the CURVE-BILLED THRASHER, noticeable, noisy, and about the size of a robin. These 67 energetic inhabitants of the cactus forests nest in mesquite clumps and cholla thickets. ”

“ 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. ”

“ In lower elevations of the Tucson Mountain Section, the gray-blue foliage of IRONWOOD is a common sight, but the species does not range farther eastward. Its wisterialike lavender-and-white flowers blossom in May and June. The nutritious seeds are harvested by rodents and formerly were parched and eaten by Indians. The wood is so dense that it sinks in water; Indians used it for making arrowheads and tool handles.
Ferns—commonly, plants of dank woods and other moist habitats—seem entirely out of place in the desert ”

“ Sid held his breath in wonderment, to see the red bath of color spread down the flanks of that huge and imposing presence, widening and broadening its base with color, bringing out the vivid green posts of [83] saguarros, the dark greens of creosote, and the white patches of barrel cactus wrapped in their dense mantles of thorns. They were in the heart of the giant cactus country now. The floor of the desert was dotted all over with them. Everywhere their weird candelabra shapes stood like sentinels, upholding bent and contorted arms, notes of bright green on a gray and pale green waste. ”