A Quick Southwest Trip: Saguaro National Park and Casa Grande

Cacti varieties at Saguaro National Park, Rincon Mountain Unit

We got to Tucson around sunset and decided to wait until the next morning to go to the National Park. The late arrival/early closing at Petrified Forest made us take more time in the morning than we had intended, which in turn got us to Tucson a bit later than we would have liked, which then took up more time the next day. That – combined with a detour to Casa Grande National Monument – got us to the Grand Canyon after dark the next day. When you have a tight trip, little delays can magnify. Luckily, we had two nights scheduled at the Grand Canyon so that we could catch up before heading home.

But, back to the subject at hand: we were up early the next morning to head to Saguaro National Park. I had booked a hotel close to the west (Tucson Mountain Unit), but we decided to head to the east (Rincon Mountain Unit) first, so that we could be closer to the Grand Canyon when done.

Tucson Mountain Unit

Saguaro National Park celebrates the magnificent saguaro (pronounced swaur – oh) cactus that grows only in the Sonoran Desert in Arizona, the Mexican State of Sonora and the Whipple Mountains and Imperial County areas of California. It also protects Sonoran Desert landscapes, fauna and flora.

I have blogged about these areas in March 2016 and March 2015.

Saguaros

The Park is a forest of saguaros

Saguaros have a long lifespan, often exceeding 150 years, and grow very slowly. It can take 75 to 100 years to grow the first of the cactus’ iconic arms (a saguaro without arms is called a spear). The growth rate is strongly dependent upon precipitation. Thus, saguaros in drier western Arizona grow only half as fast as those in and around Tucson.

Saguaro spines

Adult saguaros reach about 40 feet tall with a girth of up to 10 feet. The tallest ever was recorded at 78 feet. That's about the size of a five-story building.

The have spined ridges up their sides and, as the cactus requires more water storage, the ridges split. This is readily noticeable on most of the cacti.

Cristate saguaro

Most saguaros have rounded tops, but every now and then you come upon a crested or “cristate” saguaro. This is when the growing tip produces a fan-like form. Biologists disagree on the cause, but speculate that it is a genetic mutation or the result of an injury.

Injuries could be a lightning strike, freeze damage or when a woodpecker excavates a hole too near the top.  

More than 25 cristate saguaros have been found within the boundaries of the park. The one above is right by the Javelina Picnic Area in the Rincon Mountain Unit.

Saguaros with lots of arms

A saguaro can absorb and store large amounts of rainwater, visibly expanding and then shrinking as the stored water is used. This process enables the saguaro to survive during periods of drought. When a saguaro is fully hydrated it can weigh up to 4,800 lbs.

Saguaros produce white, waxy flowers in April through June, opening well after sunset and closing in mid-afternoon. 

The saguaro blossom is the state wildflower of Arizona. The flowers are pollinated by honey bees, bats, White-Winged Doves, hummingbirds, orioles, Gila Woodpeckers, Gilded Flickers, Verdins and House Finches. Unfortunately, we were there too early for saguaro blooms.

Saguaro blossoms, taken in 2017

Saguaro fruit

The bright red saguaro fruit that ripen in June are edible and prized by local people, especially the Tohono O'odham tribes. Because saguaros are so tall, the fruit is often out of reach and harvested using a pole to knock the fruits free. The fruit is used to make jam, syrup and wine. Native birds such as Purple Martins, Gila Woodpeckers, House Finches, Gilded Flickers and a wide variety of owls nest in saguaros. 

Gila Woodpecker excavating a hole

Excavated nest cavities form callus tissue that hardens and remains hard even after the cactus dies. The result is a “saguaro boot,” which was used by natives for storage.

Saguaro boot on display at Casa Grande National Monument

Harming or vandalizing a saguaro in any manner, such as shooting them (sometimes known as cactus plugging) is illegal. When houses or highways are built, special permits must be obtained to move or destroy any saguaro affected.

The saguaro is an important source of food and shelter for the Tohono O'odham. Saguaro spines are sometimes used as sewing needles and the ribs are used for tools and building construction.

Saguaros are supported by rigid shafts or ribs

The Park

Saguaro National Park  comprises 92,000 acres in two separate areas: the Tucson Mountain District 10 miles west of Tucson and the Rincon Mountain District 10 miles east of Tucson.

Map: Google Maps

Saguaro National Monument was established in 1933, comprising the Rincon section. In 1961, the Tucson Mountain District was added and the two areas became a National Park in 1994.

“Rincón” is Spanish for “corner” and refers to the shape of the mountain range. “Tucson” is  from the Papago-Piman words for “dark spring or brown spring.”

Ocotillo and saguaro

With elevations ranging from 2,180 to 4,687 feet, the Tucson Mountain District receives about 10 inches of precipitation a year. Elevations within the Rincon Mountain District vary from 2,670 to 8,666 feet at the summit of Mica Mountain, where annual rain and snow averages 30 inches. 

This difference is noticeable – Rincon is lusher and greener.

Precipitation in both districts falls mainly during December and January as light rain and in July and August as brief violent rains accompanied by lightning and sometimes by dust storms and flash floods.

Perhaps lightning took the top off this saguaro

Between October and April, daytime temperatures reach 70 to 80°F and nighttime temperatures may drop below freezing. In May through September, daily high temperatures average more than 100°F. 

The Park’s annual mean temperature rose from about 63°F in 1900 to about 67°F (19 °C) in 2010 and it is still rising. It was surprisingly cool when we were there, with very warm sunshine by chilly breezes.

Saguaro National Park lies within the watershed of the north-flowing Santa Cruz River, which is generally dry. Rincon Creek in the southern part of the Rincon Mountain District, free-flowing for at least part of the year, has the largest riparian zone in the park.

Geology

Saguaro National Park's oldest rocks are more than 1.7 billion years old. About 600 million years ago, shallow seas covered the region around present-day Tucson, leading to deposition of sedimentary rocks, including limestones, sandstones and shales. The limestone was mined in the late 19th century to make mortar and the area had six lime kilns. Three, all in the Rincon Mountain District, can be visited today – two along the Cactus Forest Trail and one along the Ruiz Trail.

About 80 million years ago, tectonic plate movements induced a period of mountain building in western North America that lasted until about 50 million years ago. Explosive volcanic eruptions formed the Tucson Mountains about 70 million years ago and the roof of the volcano at their center collapsed to form a caldera 12 miles across. The caldera was eventually filled by debris and lava flows, some as recent as 15 million years ago.

The Park encompasses mountains and ridges

The volcanic rocks in the Tucson Mountain District differ greatly from the surface rocks of the Rincon Mountain District because over the past 30 million years, the earth’s crust stretched and displaced rocks from beneath the western part of the Park to form the mountains in the east. Uplifted, domed and eroded, the Rincon Mountains are significantly higher and wetter than the Tucson Mountains and are home to many plants and animals that do not live in the Tucson Mountain District.

History

The earliest known residents of the land in and around Saguaro National Park were the called the Hohokam (although that was not their name), who lived there in villages between 200 and 1450 A.D. They hunted deer and other animals, gathered cactus fruits and buds and grew corn, beans and squash. Subsequent cultures, the Sobaipuri of the Tucson Basin and the Tohono O'odham to the west, may be their descendants.

Petroglyphs, etched into large stones 800 years ago, can be found in the Tucson Mountain District.

Signal Hill petroglyphs; Photo: Friends of Saguaro NP

Spanish explorers first entered Arizona in 1539-40, but non-native settlement did not occur until 1692 with the founding of San Xavier Mission along the Santa Cruz River. In 1775, the Spaniards built Presidio San Agustín del Tucsón, a military fort in what was then part of New Spain, to protect against raids by Apaches. 

The land remained relatively free of development until the mid-19th century. 

After passage of the Homestead Act of 1862, the arrival of the railroad in 1880 and the end of the Apache Wars in 1886, homesteaders and ranchers established themselves and miners sought silver, copper and other valuable ores and minerals. Mining in the park continued intermittently through 1942 and private in-holdings within the park continued until the mid-1970s.

Among the historical structures in the Tucson Mountain District are ramadas, picnic tables and restrooms built by the Civilian Conservation Corps between 1933 and 1941. Designed to conform to their natural surrounds, the rustic buildings consist mainly of quarried stone and other materials native to the area.

Tucson Mountain Unit Visitor Center, right by the entrance to the Bajada Scenic Loop

We started our morning by driving the eight-mile Cactus Forest Trail in the Rincon Mountain District.

Then, we drove across town and did the unpaved Bajada Scenic Loop, which winds five miles in the West Mountain District.

Biology
There are more than 400 species of plants and 197 species of fungi in Saguaro National Park. Plant communities within the park vary with elevation.

The wildflower season had begun

The Tucson Mountain District has two distinct communities, desert scrub at the lowest elevations and desert grassland a little higher.

The Rincon Mountain District includes these two communities as well as four more at higher elevations: oak woodland, pine-oak woodland, pine forest and mixed conifer forest.

Ocotillo

There are 25 species of cactus in the Park, including the saguaro, fishhook barrel, staghorn cholla, pinkflower hedgehog, Engelman's prickly pear, teddybear cholla and jumping cholla. There are about 1.8 million saguaros. Many invasive plants threaten the native ecosystem.

Animals

There are 30 species  of animals in Saguaro National Park; 21 in the Tucson Mountain District and 29 in the Rincon Mountain District. Animals include Mountain Lions, Coyotes, Bobcats, White-Tailed and Mule Deer, Javelinas, Gray Foxes, Black-Tailed Jackrabbits, Desert Cottontails, Ringtails, White-Nosed Coatis, Ground Squirrels, Packrats. One endangered mammal, the Lesser Long-Nosed Bat, lives part of the year in the park and part of the year in Mexico. It has been rumored that a Jaguar lives in Tucson Mountain District. Even though we entered the park as soon as the roads opened, we didn’t see any mammals except a mouse or squirrel or rat scurrying through the underbrush.

The wide range of habitats in the park supports a diverse population of 107 bird species including some, such as the Vermilion Flycatcher and the Whiskered Screech Owl, uncommon elsewhere in the United States. The Cactus Forest Drive was alive with bird song. I am sure we heard many more varieties than we actually saw. But, we did see quite a few. Including two lifers for me: the Ash-Throated Flycatcher …

Ash-Throated Flycatcher

… and the Rufous-Winged Sparrow …

Rufous-Winged Sparrow

We saw quite a few Curve-Billed Thrashers, very handsome birds with an obviously decurved bill and striking yellow eyes …

Curve-Billed Thrasher

Lots and lots of Cactus Wrens, usually perched on the sharp spines on the top of the saguaros ... 

Cactus Wrens

One little guy was singing his heart out …

An enthusiastic singer

There were, as one would expect, a number of Gila Woodpeckers, the birds primarily responsible for making the activities in the saguaros that many other birds use for nests …

Gila Woodpecker

We saw one Black-Throated Sparrow perched on a cholla ...

Black-Throated Sparrows seem to like deserts

Plus, a couple of Phainopeplas – I just got one photo of a female this time ...

Female Phainopepla

A Pyrrhuloxia that Caty captured ...

Photo: Caty Stevens

Lots of Common Ravens, including this one with a mouth full of something ...

Common Raven

..  and some Gambel’s Quail that I completely missed.

Gambel's Quail, taken in south Arizona, 2016

The park's 36 reptile species include Desert Tortoises, Diamondback Rattlesnakes (one of the more commonly seen snakes), Coral Snakes, Gila Monsters, Short-Horned Lizards, Spiny Lizards and Zebra-Tailed lizards. Despite the aridity, three amphibian species inhabit the park: the Canyon Tree Frog, the Lowland Leopard Frog and Couch's Spadefoot Toad, which lives in underground burrows, emerging to breed during summer rains. It was still too cold for any of them to make an appearance.

Curve-Billed Thrasher

Almost all, the birds we saw were on the east side; the west was very quiet. Of course, it was later in the day and, therefore, much more crowded. We had hoped to see an owl tucked into a saguaro, but had no luck with that.

Urban sprawl, air and water pollution, noise, light pollution, forest fires and habitat encroachment by human infrastructure stress the park's inhabitants.

The most serious immediate threat to animals, however, is automobiles. About 50,000 animals a year die on the Park's roads. 

Our Visit

As I said, we just took the time to do the two loop drives and visit both Visitors Centers. I wish we could have spent more time, but this was a speed trip!

Saguaro vista, left; Caty with a cristate saguaro, right

We briefly considered visiting the Arizona Sonora Desert Museum, a 98-acre zoo, aquarium, botanical garden, natural history museum, publisher and art gallery founded in 1952 that features two miles of walking paths traversing 21 acres of desert landscape. One of the most visited attractions in Southern Arizona, it is a fabulous place. But, ultimately, we decided that we just didn’t have enough time on this trip. We needed to get to the Grand Canyon, so off we went.

Casa Grande

We did make one stop along the way, at Casa Grande National Monument, which I have visited before, but Caty hadn’t.

This one square-mile park was set aside in 1892 to preserve what remained of an ancient Sonoran Desert community. 

Historic National Monument sign

The ancient people who built the Casa Grande also developed wide-scale irrigation farming and extensive trade connections which lasted over a thousand years until around 1450 when Casa Grande was abandoned. 

Archeologists call a site where there are earthen buildings, red on buff pottery and extensive canals "Hohokam," a name that has incorrectly be ascribed to the ancestors of the O'Odham, Hopi and Zuni.

Since the ancient Sonoran Desert people who built Casa Grande had no written language behind, they left no historic accounts of the Casa Grande. So, the first references were the journals of Padre Eusebio Francisco Kino when he visited the ruins in 1694. In his description of the large ancient structure before him, he wrote the words "casa grande" ("great house") that are still used today. 

Viga holes in the Casa Grande ruins

In the late 1880s, the ruins became a popular tourist stop with the arrival of a railroad line twenty miles to the west and a connecting stagecoach route that ran right by the Casa Grande. The resulting damage from souvenir hunting, graffiti and vandalism raised serious concerns about the preservation of the Casa Grande.

Anthropologist Adolph Bandelier  (as in Bandelier National Monument) visited the ruins in 1883-1884 and reported on its condition and significance. 

Casa Grande ruins

The Hemenway Southwestern Archaeological Expedition of 1887-1888, sponsored by Massachusetts philanthropist Mary Hemenway and led by anthropologist Frank H. Cushing, produced further information on the ruins' deterioration. 

As a result, several influential Bostonians urged Massachusetts Senator George Hoar to petition the U.S. Senate in 1889, requesting that the government repair and protect the ruins.

Repair work began the following year, and in 1892, President Benjamin Harrison set aside one square mile of Arizona Territory surrounding the Casa Grande Ruins as the first prehistoric and cultural reserve established in the United States.

Many of the ruins are eroded adobe

The General Land Office took over management of the ruins in 1901 and hired Frank Pinkley to be the first on-site custodian. 

In 1903, a shelter roof of corrugated iron supported by redwood timbers was built over the Casa Grande, and between 1906 and 1908 major excavations and repairs were conducted. That's when most of the lower walls were uncovered. 

President Woodrow Wilson proclaimed Casa Grande Ruins a National Monument in 1918 and management of the Ruins was transferred to the National Park Service. 

Pinkley stayed on as custodian and eventually became the superintendent of all southwest monuments.

The main part of the Visitor Center building with adjacent parking lot and entrance road, and a new steel shelter roof over the Casa Grande, were completed in 1932. Between 1937 and 1940, the Civilian Conservation Corps constructed a number of adobe buildings to support park operations. All of these structures remain in use today and are now listed on the National Register of Historic Places. As a result, the general physical appearance of Casa Grande Ruins has changed very little since the 1940s.

This ruin is covered with a large roof

Casa Grande is interesting but not mind-blowing. I am not sure our brief visit was really worth the detour (although we did get refreshing slushies at the Sonic across the street).

Cacti at Casa Grande

As a result of our stop, we didn’t make it to the Grand Canyon until it was inky dark and fairly cold.

Trip date: March 20-23, 2019