Inca Doves – small and surprising

The Inca Dove (Columbina inca) is a small dove with a body length of about 8 inches. It is smaller than a Mourning dove and the White-winged dove. The Inca Dove’s color is light brownish gray and has a scaled appearance on its back. The tail is slender and has white sides. At rest, this dove is very dull looking. That changes in flight or when the dove is displaying. Then the bright rufus-colored primaries on the underside of the wings are visible. Male doves use the display of raising one wing over their backs to defend their territory against other males.

During courtship, the male bobs its head, raises its tail high over back and spreads it widely to show off black and white markings.

Inca doves occur in the southwestern U.S. and most of Mexico. They are found around human settlements throughout much of the Sonoran Desert region. They seem to prefer open areas with sparse shrub cover and scattered trees such as palo verde and oak.

They are seed and fruit eaters. Doves grind seeds in their muscular stomachs (or gizzards) using sand or gravel much like internal teeth.

According to the Arizona-Sonora Desert Museum, “The Inca Dove has the longest breeding season of any Arizona bird: January to November. That fact, plus its preference for grass and weed seeds, have made the Inca Dove the most abundant bird in southwestern urban areas, after the house sparrow.”

According to Audubon, Nest sites vary, usually in trees or shrubs 5-20 feet above ground, sometimes as high as 50 feet. Nests (built by female, with material gathered by male) are a small platform of twigs, stems, leaves, sometimes lined with grass.

Both parents incubate the eggs for about two weeks. Upon hatching, the chicks are fed “pigeon milk” produced by both parents. “Both males and females produce this substance in their crops (the pouch just above the stomach that birds use to store food). The walls of the crop swell with fat and proteins until the cells in the crop wall begin shedding, producing a nutritious, milky-colored secretion. Despite its appearance, it’s not related to the milk produced by mammals.” – (Cornell)

The chicks fledge within two weeks of hatching and may be tended by the parents for another week or two.

Inca doves have a distinct sound. Listen here. Do you recognize it?

See also:

White-winged Doves

Mourning Doves

Eurasian Collared-Doves

The University of Arizona Guide for Snowflakes

If you plan to visit the campus of the University of Arizona in Tucson, you perhaps should read a new 20-page pamphlet produced by Jesús Treviño, Ph.D., Vice Provost for Inclusive Excellence, so that you will be politically correct at all times. The pamphlet is entitled: “Diversity and Inclusiveness in the Classroom.” (Link) This is just one of the things Dr. Treviño does to earn his reported salary of $214,000 per year. (Source)

The pamphlet is introduced with this paragraph:

“With the increase in diversity at institutions of higher education, campus communities are now commonly comprised of individuals from many backgrounds and with diverse experiences as well as multiple and intersecting identities. In addition, many campus constituents have social identities that historically have been under-represented (e.g. Black/African Americans, Latinx/Chicanx/Hispanic [sic], Asian American/Pacific Islanders, Natives Americans, LBTQIA+ folks, international students and employees, people with diverse religious affiliations, veterans, non-traditional students, women, first-generation college students, and people from lower socioeconomic backgrounds). The University of Arizona does not differ from other institutions when it comes to diversity. Considering race and ethnicity alone, currently the UA has over 40% students of color. The multiplicity of the groups mentioned above form a valuable part of our student body.”

This pamphlet was produced for both students and faculty who may occasionally find themselves outside of “safe spaces” and be subjected to or commit a “microaggression.”

Major topics include:

Understanding Diversity and Inclusive Excellence

Tools/Exercises for Preparing Students To Interact in the Classroom

Guidelines for Classroom Discussions

Dialogue vs. Debate

Microaggressions in the Classroom

Among the sage advice given by this document is this: “Oops/ouch: If a student feels hurt or offended by another student’s comment, the hurt student can say ‘ouch.’ In acknowledgement, the student who made the hurtful comment says ‘oops.’ If necessary, there can be further dialogue about this exchange.”

By the way, the document defines “microaggressions” as: “the everyday verbal, nonverbal, and environmental slights, snubs or insults, whether intentional or unintentional, that communicate hostile, derogatory, or negative messages to target persons based solely upon their marginalized group membership.” Welcome to the real world.

This pamphlet is apparently for all students whose parents never taught them how to behave in civil society.

This article was originally published in the Arizona Daily Independent  and received many comments.

See also:

Free Speech and Tender Feelings

History of the Ajo Mining District, Pima County, Arizona by David Briggs

Geologist David Briggs has written another interesting paper on the history of mining in Arizona. This 18-page paper, History of the Ajo Mining District, Pima County, Arizona, was just published by the Arizona Geological Survey and is available as a free download:

I was particularly interesting in the Ajo paper because as a geologist, I conducted exploration at the mine and in the district. Although the mine is now inactive, there is remaining mineralization that can be mined given the right economic conditions. The Ajo orebody is particularly interesting to geologists because paleomagnetic and geologic evidence indicates that the Ajo ore deposit has been tilted to the south a total of approximately 120 degrees in two separate tectonic events. (Source) There is also speculation that a detached piece of the original orebody lies hidden nearby.

Briggs begins his story as follows: “The hostile environment of southwestern Arizona’s low desert presented many challenges to those who sought to discover and exploit the mineral wealth

of the region. Ajo’s remote location combined with hot summer days and scarce water created a number of obstacles that needed to be overcome. Despite these impediments, the district’s wealth was mined by Native Americans long before the arrival of first Spanish explorers, who recognized its potential soon after establishing outposts in this region.”

The Ajo area has a long history. Prior to the arrival of the first Spanish explorers in the 1530’s, the native Tohono O’odham Indians and their ancestors mined hematite, an iron oxide, which they used as body paint. Establishment of Spanish missions in Southern Arizona provided bases from which prospectors combed the country.

With the signing of the Treaty of Guadalupe Hidalgo at the end of the Mexican American War on February 2, 1848, and the subsequent Gadsden Purchase in June 1854, many prospectors tried their luck at Ajo.

Briggs provides great detail as he recounts the many lives of mining ventures in Ajo. Following is a very brief sketch of major events.

The first formal mining began in 1855 and a wagon road was constructed to the railroad at Gila Bend. Ore was also sent by wagon to San Diego and shipped to Swansea, Wales for smelting. High transportation costs eventually made the venture uneconomic.

Briggs recounts the era between 1898 and 1908 when the Ajo deposit saw many promotions and fraudulent mining schemes.

In 1911, the Calumet and Arizona Mining Company, which was operating mines in Bisbee, became interested in the Ajo properties and acquired the New Cornelia Copper Company which owned Ajo at the time. Calumet began an extensive drilling program which confirmed the presence of a large sulfide body of mineralization. They began open pit mining in 1915.

In 1931, Phelps Dodge merged with Calumet and Arizona Mining Company and continued to operate the mine which they did until 1985 when a combination of low copper prices and stricter regulations for smelter air quality caused the company to close the mine.

The Ajo property is now owned by Freeport-McMoRan, Inc. through its merger with Phelps Dodge. According to Briggs, “Freeport continues to periodically assess the economic feasibility of returning the Ajo project to production. As of December 31, 2015, this project is estimated to contain a sulfide resource of 482 million short tons, averaging 0.40% copper, 0.010% molybdenum, 0.002 oz. of gold/ton and 0.023 oz. of silver/ton.”

Other papers by David Briggs, published by the Arizona Geological Survey:

History of the Warren (Bisbee) Mining District

History of the San Manuel-Kalamazoo Mine, Pinal County, Arizona

Recovery of Copper by Solution Mining Techniques

Superior, Arizona – An Old Mining Camp with Many Lives

History of the Copper Mountain (Morenci) Mining District

History of Helvetia-Rosemont Mining District, Pima County, Arizona


A Guide to the Geology of Sabino Canyon and the Catalina Highway

The Arizona Geological Survey has recently released a 56-page booklet which points out areas of geologic interest in Sabino Canyon and along the Catalina Highway to Mount Lemmon. The booklet is available for free download here.

The citation is:

Bezy, J.V., 2004, A Guide to the Geology of Sabinho Canyon and the Catalina Highway. Arizona Geological Survey Down to Earth, DTE #17, 56 p.

AZGS introduces the booklet:

“ Upper Sabino Canyon Road, also known as the 1 Sabino Canyon Shuttle Route, and the Catalina Highway to Mount Lemmon offer a variety of spectacular geologic features. Because of the relatively sparse vegetation in the lower part of the range, most of these features are easy to recognize and photograph. Some of these features are common throughout this southern part of the Santa Catalina Mountains. Others occur in many other parts of the American Southwest. This booklet is your field guide to the geology of this spectacular mountain landscape. All of the geologic features described in the text can be reached by short walks from the Sabino Canyon Shuttle Route or the Catalina Highway. This book is written for the visitor who has an interest in geology, but who may not have had formal training in the subject. It may also help assure that the visiting geologist does not overlook some of the features described.”

The booklet provides short geologic descriptions of Sabino Canyon and the Catalina Mountains, and describes 11 features in Sabino Canyon and 14 features along the Catalina Highway, all of which are illustrated by photographs, maps, and diagrams. This booklet can make your visit to these areas more interesting and informative.

Below are maps of Sabino Canyon and the Catalina Highway showing the location of geologic features described.



More articles on Tucson area geology:

Beneath the Tucson Valley

Gold of Cañada del Oro and rumors of treasure

Old mines of the Tucson Mountains

History of the Copper Mountain (Morenci) Mining District, Greenlee County, Arizona


The Arizona Geological Survey has just published a well-written history of the Morenci, Arizona, mining district. The report was written by geologist David F. Briggs and was published as AGS Contributed report Cr-16-C. The 79-page report is available for free download:

The Copper Mountain (Morenci) mining district is located approximately 115 miles northeast of Tucson, Arizona.

Mining began in 1873. This district has produced more than 36 billion pounds of copper from 1873 to 2015. Since 1985 is has been America’s largest domestic copper producer.

The discovery of copper at Morenci during the turbulent years of the American Civil War brought new opportunities for many, but foreshadowed the end of a way of life for Native Americans, who had lived in the region for millennia. A diverse cast of characters has played a role in Morenci’s history, including veterans who ventured west after the war, as well as immigrants eager to make a new life in America.

Briggs provides an interesting narrative of the development of the district as different companies gradually consolidated the mines. Briggs breaks the history into five phases of development as the owner(s) dealt with different types of ore, changing technology, new discoveries, and the sometimes volatile copper market.

Phelps Dodge Corporation operated the district beginning in 1917. Freeport-McMoRan Copper and Gold, Inc. (renamed Freeport-McMoRan, Inc. in July 2014) acquired an 85% interest in the Morenci project through its merger with the Phelps Dodge Corporation in March 2007, and has been operating the mine since then.

The report contains many maps and both current and historical photographs. This report is an interesting read and its story is one that was similar to that of many mines in the West.



 More reports from AZGS:

AZGS field guides to Arizona Geology

A guide to the geology of the Sedona & Oak Creek Canyon area of Arizona

A Guide to the Geology of the Santa Catalina Mountains

A Guide to the Geology of Organ Pipe Cactus National Monument and the Pinacate Biosphere Reserve

A Guide to the Geology of the Flagstaff Area

A Guide to Geology of Petrified Forest National Park

A Guide to Oak Creek-Mormon Lake Graben

AZGS Guides to Northern Arizona Geology

History of the Copper Mountain (Morenci) Mining District, Greenlee County, Arizona

A Guide to the Geology of the Santa Catalina Mountains

Cover santa catalina mtnsThe Arizona Geological Survey (AZGS) has just released a new publication that is available for free download here:
The paper citation is: “Bezy, J.V., 2016, A Guide to the Geology of the Santa Catalina Mountains, Arizona: The Geology and Life Zones of a Madrean Sky Island. Arizona Geological Survey Down-to-Earth # 22, 83 p
The description from AZGS:
This is a non-technical treatment of the geology and ecology of the Santa Catalina Mountains, Tucson, Arizona. Natural landscapes have distinctive personalities. Each is the product of the interplay of geology, climate, vegetation, time, and often, human activities. The landscapes that form the Santa Catalina Mountains of southeastern Arizona give that range a unique personality like no other in the American Southwest. Rising as a great mountain island to over 9000 feet in elevation at their summit, Mount Lemmon, the Santa Catalina Mountains are the greatest expanse of high country within the Sonoran Desert. An unusual dome-like profile  sets it apart from the numerous, steep, sharp-crested mountain ranges in the region. This distinctive profile is a legacy of the range’s remarkable geologic history and the structure of its bedrock. Formed miles deep within Earth’s crust before being exhumed, this ancient structure has guided surface weathering and erosion for millions of years. The result is a mosaic of mountain landscapes of singular beauty and complexity.
This publication contains some 83 spectacular photos and figures.  It gives a very good introduction to the geology and geological processes that formed the range and also describes its life zones.
The rocks in the Santa Catalina Mountains record 1.65 billion years of history. The publication is written for both the general public and geologists.  Take a look and gain an appreciation of that history for when you travel the mountains.

Earthquake swarm in NW AZ explained

Since March, 2016, northwestern Arizona has experienced on-going earthquake activity. To date, there have been 57 earthquakes, the largest of which registered a magnitude of 3.8.

These earthquakes are not unexpected according to the Arizona Geological Survey. They are just now being detected because of enhanced instrumentation deployment.

Northwestern Arizona is on the southern end of a seismic belt that stretches from Montana and Idaho, through Utah and into Arizona. For the past 15 million years, the crust in this area has been stretching and stretching causes faulting and earthquakes.

The Arizona Geological Survey has a 4-minute video which explains what is happening:

Natural History of Desert Bighorn Sheep

Bighorn sheep adult

Desert Bighorn Sheep (Ovis canadensis) are well-adapted to rugged, rocky desert mountain ranges and canyons. They prefer precipitous slopes and cliffs where they can be safe from predators. They have very good eyesight which helps them navigate steep ledges.

As described by the Arizona-Sonora Desert Museum: “The desert bighorn is a heavy-bodied, gray-brown, deer-sized animal with a large white rump patch. Both males and females have horns, but the males’ are much larger, growing into a curled spiral shape over the course of several years…The ewe’s horns are narrow and only grow about 12 inches long (about a half curl). The male’s horns are broad and massive and eventually curl in nearly a full spiral. The ram’s horns may weigh as much as 40 pounds.”

According to Arizona Game & Fish: “Adult males, rams, weigh between 160 and 200 pounds with a maximum weight of 225 pounds. Adult females, ewes, range from 75 to 130 pounds and average 110 pounds.” An adult has a length of 50″ – 62″ and stands 32″ – 40″ at the shoulder.

The diet of Bighorn Sheep consists of many different grasses, mesquite leaves and beans, desert lavender, fairy duster, desert ironwood, palo verde, globe-mallow, cactus fruits, and agave. In hot weather, they generally eat in the morning, then seek shade to process their cuds. “Bighorns have a complex 9-stage digestive process that allows them to maximize removal of nutrients from food of marginal quality.” In winter, the bighorns can get all the water they need by eating green vegetation. (DesertUSA)

According to DesertUSA: “Males do not defend territories but rather engage in battles over mating access to a particular female. Age as well as horn size determines male dominance status. Rutting season is in the autumn and early winter, and births take place in the Bighorn sheep spring, though mating can last from July to December. Gestation lasts from 150-180 days. One or two lambs are born from late February to May. Within a few weeks of birth, lambs form bands of their own, seeking out their mothers only to suckle occasionally. They are completely weaned by 4-6 months of age.”

Bighorn Sheep have been in the news lately because of a controversial program by Arizona Game & Fish to reintroduce the animal to the Santa Catalina Mountains near Tucson. See the AZGF page: Arizona Game and Fish Big Horn Sheep Website. I have commented on this program in a previous article: Mountain lion dietary supplementation plan.

In California, it’s Bighorns versus renewable energy: “The Bureau of Land Management issued a decision allowing the Soda Mountain Solar project to move forward on developing more than 2,813 acres of public land directly adjacent to the Mojave National Preserve that would cut off a vital route for desert bighorn sheep and damage other desert resources.

This massive, industrial solar array would block the last, best linkage for desert bighorn sheep between the Mojave National Preserve and the Soda Mountain Wilderness Study Area — a key pinch-point for keeping the sheep populations in the preserve connected to populations in the Soda Mountains and ranges beyond.” (Source)

Hunting. According to Arizona Game & Fish:

“Totally protected by the territorial legislature in 1893, bighorn sheep were not legal game in Arizona until 1953, when it was determined that the limited hunting of trophy desert bighorn rams might be the only way to save these animals. Two limited desert bighorn sheep hunts of 20 permits each were authorized, and 20 desert bighorn were taken. Since then, permit numbers, the number of units open to hunting, the number of rams taken, and hunt success have gradually increased. In 1984, Arizona began offering Rocky Mountain as well as desert bighorn sheep hunts. Between 80 and 100 hunt permits are authorized each year, mostly desert bighorns, with hunt success ranging between 90 and 95 percent.”

Bighorn sheep lambSee more photos from the Arizona-Sonora Desert Museum.

See videos from DesertUSA

A new Bighorn Sheep ram was born at the Arizona-Sonora Desert Museum on March 23, 2016. The lamb is active and on exhibit. See video:

Elf Owls

Elf owl 3The Elf owl (Micrathene whitneyi) is our smallest owl. Its body size is about the same as a sparrow (5 to 6 inches), but its wingspan is larger (13 to 16 inches).

These owls occur in southern Arizona, the boot-heel of New Mexico, the Big Bend area of Texas, and nearly all of Mexico including the southern tip of Baja. In the winter, Elf owls in the U.S. generally migrate to Mexico.

“The classic image of an Elf Owl looking out of a hole in a Saguaro cactus may be overemphasized. They are abundant in the Saguaro deserts but also are abundant into the mountains reaching elevations of up to about 6000 ft. They can be found in dense mesquite, dry oak woodlands, wooded canyons, sycamores, and probably any other tree within its elevation range. They may be seen in dense scrub and in woodpecker holes in cottonwoods or telephone poles. Classically they are in high desert, foothills, and low in the mountains, and often in dryer habitats.” Source

Elf owls eat spiders, scorpions, beetles, moths, grasshoppers, crickets and other insects. They generally hunt at dawn and dusk. They can catch prey in mid-air or pluck them off tree branches.

Elf owl 2Elf owl 4

Elf owls often nest in abandoned woodpecker holes in saguaro cactus and in natural cavities in upland trees such as sycamores, pines, and walnuts. “Males attract females to potential nest sites by calling from a cavity, then flying out while singing as she approaches. On moonlit nights calling occurs continuously all night. The female selects the nest cavity and begins to roost in it prior to laying eggs to prevent occupation by other hole-nesting birds.” Source “Breeding season in North America is normally May and June (March through August in Mexico). 1 – 5 eggs may be laid but 3 are most common. The incubation period is 21 – 24 days. The young can capture food as soon as they can fly (27-28 days of age) and fledge shortly thereafter (28 – 33 days of age).” Source

The call consists of a variety of soft yelping notes, often running together into a high-pitched chatter. You can hear some sound recordings here.

According to the Arizona-Sonora Desert Museum:

“Elf Owls, like other owls have excellent night vision. They can’t see in complete darkness, but they can see quite well in low-light. They also have excellent hearing. They can catch their prey in complete darkness, by pinpointing it using their ears rather than eyes. Elf owls have “silent flight” which means they don’t make any noise as they approach their prey. The sound of their wing beat is muffled by softened feathers on the leading edges of their wings.” Source

Elf owls are preyed upon by other owls, snakes, coyotes, bobcats and ringtails. Their life span in the wild is 3-6 years. Starlings, which are an introduced bird from Europe, pose a threat to Elf Owls. They take over nest cavities already in use by the Elf Owls, or by other birds according to ASDM. ASDM also notes that in dangerous situations, Elf owls will play dead until all danger has passed.

See many photos here.

The American Beaver in Arizona

Beaver 1Beaver 2

The American beaver (Castor canadensis) is the largest rodent in North America with adults reaching a weight of up to 70 pounds with an average of 40 pounds. (The porcupine is the second largest rodent, see my  article: Porcupines.) The American beaver ranges throughout the U.S. and Canada. It has also been introduced to parts of South America. A different beaver species (Castor fiber) occurs in Eurasia.

Beavers are semi-aquatic mammals that are most active at night. They are excellent swimmers and can stay submerged up to 15 minutes. They have webbed hind feet and a broad, flat tail which propel them through water.

Beavers build “lodges” and dams in lakes and rivers using sticks, stones, grass, and mud. Their structures often have a great (and beneficial) effect on the local ecology.

Beavers eat the leaves, twigs, and inner bark of many tree species. Fermentation by special intestinal microorganisms allows beavers to digest 30 percent of the cellulose they ingest. (source)

Beavers are prized for their fur which consists of long, coarse outer hairs and short, fine inner hairs. The fur has a range of colors but usually is dark brown. Scent glands near the genitals secrete an oily substance known as castoreum, which the beaver uses to waterproof its fur. Beaver meat tastes similar to beef, but care must be taken in preparation to avoid getting the castoreum on the meat. The characteristics of the fur led to extensive hunting and in some place, extirpation of the beaver. For more extensive general information see this Wikipedia article.

Beavers in Arizona:

According to the Arizona Game & Fish, beavers were at one time found nearly everywhere in Arizona that had permanent water. With settlement, and the desiccation of the state’s streams, beaver populations declined. This habitat loss, and in some cases, heavy trapping pressure, caused beavers to disappear from such former strongholds as the San Pedro and Santa Cruz rivers. Reintroduction programs and natural colonizations have since enabled the beaver to recover much of its former distribution, if not numbers, and these animals can now be found along several permanent streams, some of the larger river stretches, certain shallow lakes, and even a few dirt-lined canals.

The Winter, 2014, issue of Sonorensis pubished by the Arizona-Sonora Desert Museum has a good article on Arizona beavers (pages 18-23).

The article entitled “Aquatic Architects at Work: the Return of Beaver to the San Pedro River National Conservation Area” begins: “In 1826, trapper James Ohio Pattie dubbed the lower San Pedro River “Beaver River.” He and his party had been trapping beaver along the Gila River and its tributaries, but found that northern stretch of the San Pedro “very remarkable for the number of its beaver…At this place we collected 200 skins.”

The article claims: Beavers influence community diversity and ecosystem structure through tree felling and dam building. Beaver herbivory tends to result in large woody material in the floodplain, which enhances the amount of water that may be captured and stored. Water impounded behind beaver dams increases the area of riparian habitat, and, through groundwater recharge, leads to elevated water tables.

The United States Geological Survey, in cooperation with the University of Arizona recently published a paper which evaluated ecological benefits of restoring beavers to the San Pedro (read full study).

The paper’s abstract says:

We measured bird abundance and richness along the upper San Pedro River in 2005 and 2006 to investigate how beavers (Castor canadensis) may act as ecosystem engineers after reintroduction to a desert riparian area in the Southwestern United States. In areas where beavers colonized, we found higher bird abundance and richness of bird groups, such as all breeding birds, insectivorous birds, and riparian specialists, and higher relative abundance of many individual species—including several avian species of conservation concern.

After accounting for environmental factors, such as presence or persistence of surface water, and extent of Frémont cottonwood (Populus fremontii) and Goodding’s willow (Salix gooddingii), the relative influence of beaver activity was not as strong as these other environmental factors. However, there was still evidence of an association between beaver activity and bird abundance and richness, as models that included beaver-related variables better explained variation in bird abundance and richness for 71 percent of species groups and 46 percent of individual species for which we built models. Although the effect sizes associated with the beaver influence on the bird community were smaller than similar studies conducted in other regions of North America, the biological significance of beaver activity in the upper San Pedro River riparian area will likely become even stronger with increasing time.

AZ Game & Fish studied the suitability of re-establishing beavers in Cienega Creek. The 2008 study concluded that certain reaches were suitable.

You can see beavers at the Arizona-Sonora Desert Museum. ASDM has a story about a “beaver breakout” from the Museum. “One night, the beavers left their pond, waddled through the bighorn enclosure and escaped into the desert. The next morning Museum people followed their tracks, which headed west and before long stopped near a set of coyote tracks. Swirling beavertail prints in the sand showed how the beavers had made an about-face and headed back to the safety of their pond. They never attempted another escape.” source

See Article Index for more stories.