Eating Stone (9 page)

Eighty-five miles long, running north-south in a graceful narrow arc, the San Andres Mountains lie entirely within the 3,500-square-mile White Sands Missile Range. They are one of the West's accidental wildernesses, vast tracts of desert left “pristine” (not counting the waste dumps and bombed sectors) by the military's huge need for huge geography. The San Andres Mountains have been closed to mining and domestic grazing for half a century. Public access is prohibited.

As often as twice a week, the missile range closes the highway across the mountains, from the Tularosa Basin on one side to Las Cruces and the Rio Grande on the other. The lockdowns last about an hour, while the army lobs scary devices across the New Mexico skies. Occasionally, the Border Patrol, also busy around here, throws up roadblocks, and agents check each car.

For illegal aliens, civilians, and sheep, movement across this broad expanse is not easy. The wild bighorns in the Southwest's island ranges live in permanent lockdown. They can no longer easily trot off in a free exchange of populations. Studies have shown that fenced freeways, for example, are influencing gene-flow patterns.

In the valleys between southwestern mountain ranges lies a maze of treacheries. Roads, bombing ranges, fences, cement-lined irrigation canals, four hundred acres of broccoli plants, shopping malls—how does a sheep tiptoe around a Home Depot?—ATV trails, golf courses, subdivisions, RV resorts full of thawing Min-nesotans. Entire cities. A few sheep negotiate barriers and cross the basins between mountains, turning up far from their asylums, surprising the hell out of everyone.

I manage to drive through without a lockdown, a roadblock, or screeching overhead rockets. Before I head into Las Cruces, I pull over on a side road to walk and stretch. The road deadends at a grim steel gate marked restricted area—do not enter
.
I wonder if the soap-tree yuccas hold surveillance cameras. I face one of the yuccas—green spikes atop a pedestal of brown spikes, a sort of electrocuted palmetto—and I wave, assuring the generals that I am just another harmless patriotic dissident. I take a look at the mountains.

The San Andres fault block rises even as it wears down, filling the surrounding basins with the debris of its past, in alkali flats, malpais, beds of quartz sand, and playas of snow-white gypsum. Every mountain range has its own personality. It tells you about
itself when you feel its firm terrain under your feet and ask a thousand questions. This one, I must explore largely with my own imagination. I see it as a sky-raking sierra with one of the world's most social creatures, all by herself. I am not yet sure what matters here.

Spokes of sunlight stream down from holes in the heavens, illuminating bands of malachite on flanks of Prussian blue. The green drifts across the shadowed blue in a net of light, marine in its motion, as if the mountains were not under a storm, but under the sea.

A stratum of cloud rings the shoulders of the highest peaks. Above it, the crests float clear. The escarpment draws rain and starves the valleys. It rises abruptly from pale green bajadas to ragged precipices, from creosote to bare rock and a bald ewe, all in a single breath.

She is not a Nelson's bighorn like the sheep in the Blue Door Band. Her race, Ovis canadensis mexicana, is deeply southern, found in the Sonoran and Chihuahuan deserts of the Mexico-Arizona–New Mexico borderlands. It is believed that New Mexico, western Texas, and Coahuila may have once marked the eastern limits of its range. In southern New Mexico, sheep habitat, even without human influences, may have always been sparse, scattered, marginal. Historically, some of the best of this habitat lay in the San Andres Mountains.

She is not the only desert bighorn in New Mexico. Small populations of “questionable viability” hang on by a hoof in other mountain ranges. Some of those herds include stock that was transplanted from other places in efforts to keep the species in its historic range.

Ewe 067 lives on the San Andres's southern end in a federal wildlife refuge that predates the military reserve. The bears and wolves are long gone. The top predator, not counting the B-52s, is the mountain lion. When the refuge was established in 1941, it
held thirty-three bighorns. Protection favored recovery, and the herd began to grow.

In the 1960s a San Andres National Wildlife Refuge publication noted, “These shy and majestic mountain bounders are well adapted to their rough mountain habitat. Continued studies are being conducted to better insure that this rare species may never cease to be a part of our North American fauna.”

In gross understatement, it has not been easy.

The desert bighorns of New Mexico are cat food. Several hundred pounds of them have passed through the digestive tracts of opportunistic Puma concolor. Such a relationship may sound as obvious as roadkills on a Nevada highway.

Mountain lions are exquisitely designed to kill ungulate prey. If lucky in the hunt, they can eat ten pounds of meat at a sitting. Cryptic stalkers, they shape-shift the colors of desert rock and shrub. They travel widely and show up in places where they weren't.

Mountain lions favor mule deer but will take a bighorn incidentally if they encounter sheep while hunting their preferred prey. Mountain lions may run low on deer and hunt more intensively, moving through a broad territory in search of food.

If the bighorns are weakened by disease and drought, if they are isolated remnants with low numbers, or if they are transplants from elsewhere that have yet to map their escape terrain, the big cats may have a profound effect on them. Mountain lions that become frequent killers of endangered bands of bighorn sheep may earn a tracking collar, the tag “habitual offender,” relocation to elsewhere, or, in some cases, a death sentence.

Quite successfully, bighorn sheep elude mountain lions due to their acute vision and the pooled vigilance of a large herd. They flee to safe ground on pinnacles, ledges, and fissured cliffs, places
that hide them or throw verticality into the path of their pursuer. More commonly, bighorns avoid mountain lion country, a sort of “Let them eat venison” tactic.

In the mountains of southern New Mexico, none of this appears to be working very well. If the design of bighorn sheep aspires to starve mountain lions, here the sheep lost the odds.

More clouds engulf the mountains, draping thin silver veils into the bajadas that skirt them. A squall approaches, christening me with wind gusts and the aroma of damp creosote. Using the truck tire as a wind shelter and backrest, I sit on the rough ground and await the rain.

In the morning, I will visit the world of SAE 067 with the refuge manager and hear her radio signal as it blips from the heights. I understand that I may not be able to see her, but I feel sharp pierces of longing to do so. The desire is mine, wholly selfish. In the photograph, she has a helicopter in her face. Is that not enough disturbance?

The camera freeze-frames a hornless gray-colored bighorn sheep against blue-black rock, a red dot of an ear tag, a radio collar around her neck. The lamb leaps beyond the frame, a coil of springing muscles. Considering the noisy steel locust that hovers above her, the ewe looks remarkably still and stoic. Yes, I had this lamb by immaculate sheep conception, she seems to say. The die-off of her herd mates, the aloneness. A broken leg, both horns knocked off. The chopper. And I haven't even begun to tell you about the mountain lions.

The squall delivers weather with muscle, sending me inside the truck for cover. Behind sheets of sleet, the mountains dissolve. The pelting is furious for a while; then I slip over a pass between the San Andres and Organ mountains, underneath the sunlight that reveals itself behind the ice storm.

Only sheep and lions fully understand sheep-lion dynamics. In the past decades, however, the stewards of the San Andres National Wildlife Refuge have had little choice but to try. The lions are intensely studied, as are the bighorns. The efforts to preserve the San Andres herd fall into the category of herculean tasks.

This is how the indigenous Chihuahuan Desert bighorns came down to one ewe.

From the thirty-three animals in residence at the refuge's creation in 1941, the San Andres population began a healthy trend of increase. With this chunk of New Mexican outback closed by the military, mining and grazing ceased, and range for wild sheep improved.

The sheep survived the world's first atomic-bomb blast, less than a hundred miles beyond their mountaintop. They fed and bred beneath rocket tests, sonic booms, screaming jets, and missiles called Patriot and HAWK (Homing All the Way Killer). Their neighbors were a gaggle of accelerators, a fast burst reactor, something freaky called BAT (Brilliant Anti-armor Submunition), and who knows what else that has never emerged from the vaults of military secrecy. What the sheep could not cope with, thrown at them in the years to come, would be bug damage in their ears.

After a setback in the fifties, largely due to drought, the population rose again. From 70 sheep in 1955, it grew in twelve years to 270 sheep. That fat herd of 1967 stands at a high in reliable records. (Some biologists set the number at a more conservative 200. There is speculation that, even in “pristine” times, 150 to 200 animals may be the San Andres's carrying capacity for the species.) On this mountain, the bighorn sheep show patterns of low genetic variation, a sign of inbreeding, and a history of fluctuations: a cycle of crashes to low numbers, followed by gradual increases.

Although wildlife science has made vast leaps forward, population dynamics—the balance of birth and mortality, plus enough complex factors to incite nosebleeds—still evoke guesswork and differences of opinion. In general, herds expand when conditions are favorable. Mortality adjusts the population to a new situation, such as climate changes or food shortages.

When mortality is high, a herd may reach a low point from which it cannot recover. (Although the number is controversial, some biologists set the “minimum viable population” at fifty animals.) Sadly, this may be the story of many of the Southwest's lost sheep. It could leave the Blue Door Band thirty animals away from a similar fate.

In the mid-1970s, counts in the San Andres came in at around two hundred sheep. Ram hunts were allowed, controlled and sparingly, so that some animals could be taken without jeopardizing the herd. The last ram hunt on the refuge took place in 1978.

One of the perils of island life is susceptibility to disease. With its high degree of sociability, a herd can be a petri dish for contagion. Serious disease predisposes animals to predation, to continued and new disease, to poor nutrition and reproduction. Too weak, a population may fall into a downward spiral. Too rare— a species low in density or geographically isolated—they face a thin threshold for collective disaster.

In their holdout enclave, the San Andres bighorns were hit by a virulent outbreak of scabies, a disease caused by ectoparasitic mites. Scabies mites inflict a variety of disorders that can reduce an animal's health and vigor: hair loss, crazed itching, folding of the external ear, plugged ear canals, eardrum damage, loss of hearing, and upset equilibrium. A normally agile sheep with clinical (severe) scabies can lose its muscular coordination and accidentally fall off a cliff and break its legs or crack its skull.

The San Andres scabies-mite infestation was sudden and severe. Sheep counts in 1979 revealed seventy-five to eighty ani-
mals, down from two hundred in an alarming crash. Scabies may have predisposed them to another affliction, a virus called contagious ecthyma, which can lead to blindness, lesions, impaired feeding, and starvation. From 1979 into the next decade, 85 percent of the herd died.

Domestic sheep, goats, and cattle, as well as wild ungulates, attract mites; the relationship between mites and host is murky. How Psoroptes spp. mites were originally passed to the San Andres ungulates was never clear, either, although many agree that the mites likely came from domestic livestock introduced to the region in the early 1900s. The parasites may have long been present, possibly cyclical, possibly dormant, perhaps residing in a reservoir host such as mule deer, then became manifest in the bighorn epidemic.

In 1979, refuge managers began a salvage operation. They captured forty-nine sheep from the mountain and treated them for scabies. For some, intervention came too late. Accidents and disease-related losses in captivity further reduced their numbers. Only twelve survivors of the roundup would return home, there joining transplants brought in from another area. In 1980, the desert bighorn sheep was listed as an endangered species in New Mexico. In early 1981, the San Andres herd back in the wild numbered about forty sheep.

Over the next fourteen years, annual refuge surveys counted a herd that stayed below forty but above twenty sheep. Disease continued to plague them. The local mule deer population declined and mountain lion predation intensified. Mutton was on the menu. When San Andres bighorns died, mountain lions were the proximate cause.

By 1997, the desert bighorns native to these mountains were extinct, one ewe short of zero.

In the many places across the American and Mexican deserts now empty of their native wild sheep, perhaps that is how the end
unfolded, absent of witness: fewer and fewer animals, a dazed gang of old rams in a boneyard of their companions, peering down from their day beds, no future. Five sheep, three sheep, then two, then one, all by itself. Then zero.

On one of the world's most restricted and secretive military reserves, home to earthbound and space technology so sophisticated, it makes your brain itch, the security gate at one of its entries is… well, broken. An actual human being replaces the robot box that reads pass cards. The guard is friendly and pleased to see us out in the middle of nowhere with him. After a brief chat, he waves us through.

Kevin Cobble, my escort, is the manager of the San Andres National Wildlife Refuge and a man with a security clearance. He is a tall, slender forty-six-year-old in a brown uniform, with the “untiring efforts” look of someone who works with rare wildlife. Back in his office, I thought I spotted a bulletproof vest stuffed into a pack, but it had a lot of dust on it.