On a blazing morning at the end of August, he's bouncing north along Old Ruggles Road just west of Arivaca, a little town of ranchers and hippies some 10 miles north of the Mexican border. The dirt road might as well be called Old Rutted--it's that rough--but McCullough doesn't seem to mind. At 75, the snowy-haired scientist still loves driving his giant 4x4 into the wilderness--the "tulies," as he calls them--and getting out to hike through the spiny desert.
"I was a field geologist for years," he says, explaining away his impressive fitness. Some days, he admits, he treks for 12 hours, drinking water as he goes from the camel pack strapped to his back.
During his university days, he studied geologic hazards in the desert--what happens when rainwater floods the land or, conversely, what happens when too much groundwater has been pumped out underneath. Now, when he strides out into the desert on his long legs, he's not looking for land slides, or earth cracks, or other signs of subsidence.
Instead, he's searching for trash and clothes and footprints, the traces of human beings.
"There's the trail over there," he says, easing his huge vehicle to a stop in one of Old Ruggles' deepest ruts. To our right, up a hill on the east, he's spotted a path threading through the cactuses and mesquites.
When he climbs out, he sees two pairs of men's pants and two water bottles lying at the bottom of the hill. When he walks up the slope, he finds a couple of bottle caps and a mud-caked backpack, sure signs that this prickly path has been trod by undocumented migrants. It's one of scores of treacherous Arizona trails that border crossers walk to get farther into the United States.
"The deaths are taking place all along these corridors," he says.
What McCullough wants to know is: How recently did the owners of these pants pass by? And how far did they continue along this trail? He intends to find out by walking it himself, for miles, calculating the age of its trash, and mapping its every twist and turn.
He's been doing this for the last three years, marshalling his science skills to mitigate the humanitarian crisis of migrant deaths in the desert. If he can get accurate maps into the hands of volunteers, and tell them where the migrants are walking, maybe, just maybe, they can find travelers in trouble and help them before they die.
"What I'm doing is a teeny, tiny Band-Aid on the whole thing," McCullough says. "We're looking at 1,800 square miles, and 5,000 miles of trails. We think we know where the trails are, but we've only mapped about 20 to 30 percent of them."
He sets off on this new trail through the mesquites, the sun glancing off the leaves, yellow butterflies flitting through the grasses. It's monsoon season, and the desert is refreshingly green, but at 101 degrees, it's hot. Make that broiling.
"This is a great time of year!" McCullough exults as he zips along. "And this is a great county for quartz," the geologist in him adds, kicking at a white rock. "One of the nice things about being out here is you see Gila monsters, tarantulas and dung beetles."
And water bottles. They litter the rocky trail, and McCullough gives them a once-over with his scientist's eye. He knows all about their life cycle, having once conducted an experiment in his Tucson driveway to test their longevity. He filled a plastic bottle with water and left it out in the sun to see how long it would take for the plastic to break down.
"In six weeks, it's brittle," he says, demonstrating on an old bottle on the trail. He grasps it, and it cracks. Ancient history. The migrant who quaffed that water passed through here before mid-July.
Next, McCullough picks up a man's shirt that's caked with mud.
"Now this has been through several rains," he judges, meaning it was probably dropped more than a week ago. Next, he finds a footprint, but the storms have smudged its edges.
"Every time you get rain, it's like erasing a blackboard," he says.
He's got a rating system, one to five, for the trails, with one going to cold, unused routes and five going to hot paths where he encounters live migrants. For now, he awards this one a low two: It's been traveled, but not recently.
McCullough hasn't forgotten his mapmaking. A GPS unit dangles from a cord looping around his neck, and every 300 feet, he pushes a button on it to record a "waypoint." Magically--or scientifically--a virtual trail takes shape on the GPS screen. He's creating a map of the trail, bit by bit. When he gets home from his hike, he'll feed it into a computer and print out an up-to-the-minute map for the activists trying to save lives.
On his treks, he ranges through a region that stretches 30 miles along the border, from Nogales west to Sasabe, and north about 50 miles, from the Tumacacori Mountains on the east to the Baboquivari on the west.
"There are three main corridors from the border," he says, each with three or four trails. "They meet up north of Arivaca Junction. The Border Patrol knows all about it."
And in a never-ending cat-and-mouse game, once the Border Patrol zeroes in on a particular path and arrests illegal migrants there, the coyotes--people smugglers--quickly change their routes. And just as quickly, the activists and agents try to alter theirs. The maneuvering reminds him of the adaptations of evolution.
"It's Darwinism," McCullough declares.
In 2004, the first summer that assorted activist groups in Tucson joined forces to create No More Deaths, McCullough and his wife, Debbi, an artist, volunteered down at the group's base camp in Arivaca. Like the others, they'd walk the desert, looking for migrants to help. But there wasn't enough information to suit him. No hard data.
"We'd go out onto the trails, but you had no idea where they went. When you came back in (to camp), you couldn't tell anyone where you'd been. We were just wandering. There was no systematic approach. I didn't like being out there and not knowing where I was."
Likewise, the Samaritans, who roam the countryside in vans and walk into the desert, "had no records or maps." So the retired geologist formulated a plan.
"The first thing, I drove the ranch roads in low gear. They're all dirt roads. Some haven't been used for years. My father-in-law went with me. I'd look outside one way; he'd look out the other. When I saw a trail, I'd get out and map it.
"A pattern started to emerge. The migrants are mostly going out of Nogales and Sasabe, heading northeast to Tucson. Since they were going northeast, I'd drive roads going northwest. And the trails would cross the roads."
Many of his fellow activists are "faith-based," but McCullough is not a church-going man.
"I was raised Southern Baptist, and that was enough to make me not religious," he says, laughing, his voice still slightly tinged by the soft accents of his native West Virginia. "I was not always interested in immigrant issues, but when people started dying ... ." His voice trails off.
"What makes me mad is you've got a problem, and nobody is addressing the causes."
The problem is that people are dying out there, in Arizona's desert cauldrons, of heat stroke and dehydration and exposure and hypothermia. This year was more deadly than the last, with the desert yielding up more bodies, of men and women, of the young and the not so young.
On Aug. 29, for instance, the day before McCullough mapped the trail near Old Ruggles Road, Juan Montes Mendez, a 51-year-old Mexican man, died of exposure about a mile southwest of Sells, on the Tohono O'odham nation. And Sonia Alvarado Soriano, a 25-year-old woman from parts unknown, likewise died of exposure outside Douglas.
The day before that, Aug. 28, the body of a 22-year-old Mexican woman named Maria del Carmen Sanchez Hernandez landed in the morgue at St. Mary's Hospital in Tucson. A 26-year-old Guatemalan, Ana Maria Yaxon Chavez, was in the holding freezer at Tucson Medical Center. Ana Maria's cause of death: complications of hyperthermia and dehydration.
"This year, we're already at 222," says Kat Rodríguez, referring to the bodies of border crossers found in Southern Arizona from Oct. 1, 2006, through Aug. 31. Thirty-two bodies were recovered in June, 52 in July and 22 in August.
And the 222 figure doesn't even include the final month of the fiscal year, September, whose carnage has yet to be calculated. By contrast, last year, for the whole fiscal year to Sept. 31, 2006, Rodríguez tallied 206 bodies. Anyone who hoped that was the beginning of a downward trend was disappointed: Last year's dip turned into this year's spike.
Rodríguez, of Coalición de Derechos Humanos, a human-rights organization based in Tucson, each year works on the grim task of compiling the deaths, gleaned from figures she gets from the medical examiners in Pima, Cochise and Yuma counties. But she cautions against calling her numbers death tolls, because the real numbers could be far higher.
"We don't have any idea of the actual number of deaths," she points out. "We call them recovered bodies."
After all, she says, skeletons are always being found. Some of the bleached bones lie in the sand for years after their owner's actual death. On Sept. 28, for instance, skeletal remains were found near Sells. Border Patrol agents couldn't determine the dead person's gender, and the date of death may never be known. Some bodies are never found at all.
Weather plays some role in pushing the deadly numbers up and down. "Last year was cooler; the monsoons came soon, and this year, the weather is (worse)," Rodríguez says. This summer's average high was 99.7 degrees, a whole degree hotter than last year's. Still, she blames this year's higher numbers primarily on the "militarization" of the border. With the national arguments over illegal immigration reaching a fever pitch, the feds have increasingly fortified the international line between Arizona and Sonora.
"The Border Patrol argues that the border is more sealed than ever," she says. "But people are forced to shift routes into more dangerous and desolate areas. The deaths spike. Militarization has never been successful in controlling immigration. It only shifts the flow."
It's true that agent numbers and barrier miles have shot up. Just in the Tucson Sector, which covers all of Southern Arizona except for Yuma County, the Border Patrol has added 18 new miles of fence and 27 new miles of vehicle barriers in the last fiscal year, says Border Patrol spokesman Jesús Rodríguez. And some 100 to 200 new agents have been deployed.
The total number of agents is classified, a Homeland Security secret, he says. Suffice it to say that there are plenty, so much so that Arivaca feels like an occupied town. The morning McCullough drove through the once-sleepy little burg, four Border Patrol SUVs were out and one cruising the road. A fifth went by later hauling a horse in a trailer. A Wackenhut bus--chartered by the feds to carry captured migrants back to the border--clattered by. And while he was out hiking the trail, a Border Patrol helicopter passed overhead.
The agency has also erected nine surveillance towers, two on the Tohono O'odham land west of the Baboquivari, and seven between Sasabe and Arivaca. But they've become something of a local joke. The pricey towers are not yet operating, Rodríguez concedes. "They're working out minor bugs."
Jesús shares Kat's last name but not all of her views. Like her, he partly blames the weather for migrant deaths.
"Remember how much it rained last summer?" he asks. "This (death spike) is because of the lack of rain and the heat index."
But the principal culprits, he says, are coyotes who leave their customers to die.
"The smugglers give (crossers) 'triple stackers,'" a pill officially called Sedalmerck that combines caffeine, aspirin and ephedrine. "They give them those pills, and say, 'This will give you energy.' They dehydrate you faster."
Border Patrol agents are "doing our part to minimize deaths in the desert. We have BORSTAR (the elite rescue teams) out. Our job is to secure the border, but at the same time, we wear our rescue hats and save people. Our job is not to lead people out to the desert. We're not the ones that take them out to the desert--they (coyotes) just leave them there."
In the past year, he adds, the Tucson Sector agents rescued 554 people in 176 incidents. At least one of those times, the rescue wouldn't have happened if McCullough hadn't been out in the field.
While tracking in the flatlands--the "alluvial plain," the geologist calls it--west of the Sierrita Mountains, McCullough came upon two stranded young men.
"One had severe knee problems and couldn't walk," he remembers. "They'd been there four days. They'd built a fire trying to attract the Border Patrol. Fortunately, they were near a water tank. We called Border Patrol, and they sent a helicopter."
The young men "were tickled," he says. "Usually people (in that situation) are starting to have a fear of dying out there."
But McCullough's data show that the increased patrols and surveillance have, in fact, pushed walkers farther into the dangerous desert. Before the crackdown of the last few years, migrants walked 10 miles, maybe a day's walk from the border, to Arivaca Road, where they got picked up by their rides, he says. The evidence is in the 3-year-old "drop piles" of backpacks and clothes he's found alongside Arivaca Road.
Now, most migrants hike the back country for many more miles, and more days, to avoid the patrols and the heavily policed roads. And the longer people are in the desert, the greater the danger. McCullough plots the death locations on his computer maps, and his findings correlate with Humane Borders' data: "The peak deaths take place at 40 miles."
"Because of the increased number of agents, the farther the migrants have to walk, the more are going to die," he says.
McCullough is not the only scientist trying to apply rational solutions to the vexing problem. Dr. Samuel Keim, a UA physician, professor and researcher in the Department of Emergency Medicine, sees the deaths as a matter of public health. He's set up a Web site that calculates the correlation between rising daily temperatures and the risk of death.
"Ten years ago, we began to notice in the local media reports of people dying of heatstroke when they were trying to cross the desert," he says. "They were also coming to the emergency room. I do academic research in community medicine, and this was something new."
Working with Pima County Medical Examiner Dr. Bruce Parks, Keim began tracking the heat deaths.
"We compared the dates of death for four consecutive years, and their association with the ambient high temperature on a given day. We could accurately predict the probability of one or more heat deaths on that day in Pima County."
His Web site,
borderrisk.med.arizona.edu/crossingRisk.html , in English and Spanish, gives a six-day forecast, and lists the probability of a death on each of the days. Last Saturday, Sept. 29, had a forecast high temp of 90, for instance, indicating a 12 percent risk. The forecast for Wednesday, Oct. 3, of 94 degrees pushed it up to 20. Keim's goal, quite simply, is "the prevention of further heat deaths."
Likewise, the UA's Gary Christopherson, director of the Center for Applied Spatial Analysis, is putting together a database pinpointing the location of the desert deaths. Humane Borders uses his information to set up its water stations in the most perilous sites, says Humane Borders executive director Sue Goodman. The data show that "water stations can help save lives."
Christopherson also calculates "how far from the roads the deaths occur," Goodman says. And he's learned something interesting. "Every year, they occur farther from the roads"--which, of course, are heavily monitored by the Border Patrol.
And which is why McCullough treks so deep into the desert.
On his Aug. 30 hike, the farther he goes, the more evidence he finds of recent human travelers. A Santo Niño de Atocha water bottle--bearing the popular image of the boy Jesus as a pilgrim--is fresh and pliable. He discovers an active windmill, watched over by a herd of placid white cows, where migrants could easily pump out fresh water. Nearby are more bottles. He comes across an unrusted can of Red Bull, a popular migrant drink that's "the equivalent of five cups of coffee," and an empty electrolyte bottle, another migrant necessity.
"You can drink lots of water," he says, "but if you get no electrolytes, it don't make no nevermind."
A sock hung in a prickly pear, a shirt in a grove of trees, a pair of brown boots with the soles coming off--all of these come before the prize: a fresh footprint, stamped by a tennis shoe after the recent rains.
"This was made in the last day or so," McCullough says. "I'm upgrading this to a No. 3. I don't think there's any doubt we're walking a migrant trail."
McCullough enjoys a certain mythic status on campus as the UA prof who won a bundle in the Arizona lottery, but he has plenty of compassion for the impoverished migrants whose trash he's tracking.
"You can't go out there and run into people and see their situation and not feel something," he says.
He's encountered a young man trying to keep his ailing aunt alive; a pregnant 17-year-old ready to give up; a husband and father of two who left home and risked his life to keep his family going. That man wasn't worried about the bandits who prey on migrants, or la migra, who send them back home, McCullough says, but he was "deathly afraid of dying in the desert. That was his big fear, but he came anyway. That tells you something."
And he's gotten kindness in return from travelers. One group of robust young people in their 20s, alarmed to find this white-haired grandfather miles from nowhere, offered him their own precious water.
Plenty of scholars predicted the onslaught of these largely rural migrants from Mexico before NAFTA was enacted back in 1994, McCullough says. With corn flowing freely from the United States into Mexico, researchers calculated that hundreds of thousands of farm workers would lose their livelihood, and the means of supporting their families. And that's just what happened. The displaced workers fled in torrents, to take up new American lives as crop pickers, meat packers, construction workers, nannies and housekeepers.
"Papers were written, predictions were made that people would come to the U.S.," says McCullough, who visited the southern state of Chiapas last year to see firsthand the villages emptied of working adults. "The whole thing was just ignored."
So McCullough does what he can. And so do others, in Nore More Deaths, the Samaritans and Humane Borders. A couple of volunteers, Dan Millis and Gene Lefebvre, a retired pastor from Phoenix, spent eight weeks this summer mapping as many trails as they could.
"I have no doubt we've saved a number of people this summer," McCullough says. "But most of the July deaths were on known trails. If we had more volunteers, we could have saved them."
So there's not much time for rumination. He's got work to do right now.
And off he trots, at breakneck pace, through creek beds, under low-lying mesquites, around prickly pears, up into the saddle of a mountain, clicking on his GPS as he goes.
After all, as he says, "We need more information."