To an outsider, the desert here appears an inscrutable keeper of secrets, pale and vast and hypnotic in its sameness.
But Glen Payne reads it like a book. His practiced eye can mean the difference between life and death for undocumented migrants who cross into one of the nation's most desolate and unforgiving tracts.
Payne, a U.S. Border Patrol agent, has spent more than two decades teasing clues from the crusty desert floor--a scuff mark here, an upturned stone there--that betray the routes taken by migrants once they have sneaked across the border southeast of Yuma, Ariz.
Most of the time, Payne and the 42 agents he supervises are out to make arrests. But come late spring and summer, when temperatures top 110 degrees and water is even scarcer than shade, the agents' skills as trackers swiftly can turn them into rescuers. It was in the heart of this bleak, 3,000-square-mile expanse that 14 people died of dehydration and 12 others were rescued in May.
Each day, agents in trucks prowl a web of primitive, sandy roads, searching for subtle--sometimes grim--signs of the trekkers. In proper light, a trail of footprints shows as tiny shadows, dappling the soft gravel like droplets on paper. Long scuffs may suggest the hiker is falling ill. A knee print might signal collapse. A meandering trail or cast-off clothing can indicate the delirium that precedes death in severe heat.
"Any time you've got a trail and temperatures are 100-plus, you've got to move quick. Or if you find discarded clothing, you know darn well something's not right," Payne said, guiding his Border Patrol truck one recent day, checking for tracks. "We come out here in an enforcement mode, but it can turn into a rescue or humanitarian mode in no time."
As the United States has clamped down along other parts of the 2,000-mile Mexico border by pouring in small armies of agents--bolstered by high-tech movement sensors, night-vision scopes and infrared eyes to detect illegal entries--Payne's team relies mainly on the ancient art of tracking, which agents call "sign-cutting." While the Border Patrol has planted seismic sensors in key spots of this 62-mile segment, the area is too big, and agents too few, to rely on much else than simply eyeballing the ground.
"These ground trackers--I don't know any better. Nobody does the kind of stuff we do. The military doesn't train for it. It's pretty unique," said Maurice Moore, the Border Patrol's assistant chief for the Yuma region, which includes the Wellton area.
For Payne's team, the desert is a giant slate on which are scribbled telltale clues for those attentive enough to spot them. Agents maintain about 100 miles of gravel tracks, smoothed each day, sometimes several times, by trucks towing a chain of tires laid side by side. ("Our big eraser," Payne says.) The result is a grid of roads, blank as newly groomed ski slopes, that make it easier to detect footprints.
Once they detect tracks, the agents methodically follow them, on foot or by driving ahead to see if the trail shows up farther north. The hunt often is joined from the air by helicopter pilots skimming above the ocotillo cactuses and paloverde trees in search of more tracks.
Agents must read the footprints in sufficient detail to gauge the size of the migrant group, so all are accounted for at the end of the search. The trackers talk to each other in an arcane lexicon of shoe-tread patterns: wavy line, starburst, gear border, heel within a heel. Bare feet are harder to follow. Lacking sharply defined lines, they tend to leave only a shiny spot where sand is pressed slightly into the firmer subsoil.
The tracks often bear clues about when they were made. Those skirting neatly around bushes probably were left in daylight, when the hiker could see. Those slashing through the brush were likely left at night. Even the presence of bug trails or animal tracks, typically left at night, can help agents estimate when the human prints were made.
"You have to look at all of it," the 53-year-old Payne said.
Footprints endure well here, but tracking is made difficult by the subtly varied desert surface--light, nutty gravel giving way to darker, packed earth and to tumbles of black volcanic rock. The search for survivors during the May incident was hampered by rocky terrain that revealed few footprints. (One measure of the harshness of the search area, in the remote San Cristobal Valley, was that Border Patrol trucks suffered 26 flat tires during three days of hunting.)
Smugglers and migrants know about the trackers and try to elude them. They craft tread covers from foam mats and squares of carpet, tricks that agents say work pretty well. Migrants sometimes walk in single file to disguise their tracks, or swipe away prints with a tree branch.
But it is next to impossible to traverse this area without leaving a trace, agents say. It is those traces, what trackers call "sign," that agents must spot amid greasewood bushes and ironwood trees, darting lizards and the ubiquitous tracks of rabbits and coyotes.
"Sign can be everything, from a cloth, cigarette butt, a piece of paper, discarded clothing," said retired agent Joe McCraw, who remains something of a legend here for his superb tracking abilities.
Sometimes, agents find just a sliver of track. McCraw recalled how the failed search for a 9-year-old boy while McCraw was an inexperienced border agent near El Centro during the 1960s long haunted him. McCraw said he passed over two scrapes in the dirt, realizing only later that what he had seen were the child's indistinct tracks. The boy, a U.S. citizen, ultimately was found on a mountainside, dead from a fall, McCraw said.
"I didn't have sense enough at the time to know what I was looking at," McCraw said. "Nine times out of 10, you're not going to see a whole track."
That reality requires persistence and patience, commodities often in short supply among some new agents, whose 19 weeks of training at the Border Patrol Academy includes just one hour devoted to sign-cutting. Payne said recruits often drive too fast to spot clues that may show up as little more than a broken branch.
This day would be uneventful for Payne. Crossings here have plummeted since the well-publicized May tragedy. Wellton agents arrested 66 migrants in June, fewer than half the total during the same month a year earlier.
Nonetheless, officials are considering installing a string of 30-foot beacons, each equipped with a flashing strobe and panic button so migrants in distress can summon help from deep in the desert. The proposal is opposed by environmentalists and others as an intrusion into sensitive desert habitat.
For now, migrants in peril must find agents, or hope agents find their tracks. The desert offers little succor, a truth veterans such as Payne have seen proved time and again.
"You find men, women, children, all of them," he said. "In all categories: deceased and survivors."