DULZURA, Calif. – Immigrant smugglers once avoided the rugged, chaparral-covered canyons east of San Diego for easier crossing points — but now the Otay Mountains are one of the busiest areas along California's border with Mexico.
As smugglers try to stay a step ahead of the law, the U.S. Border Patrol has followed with its only unit of agents who are ferried around in helicopters and then set out on foot in search of illegal immigrants.
The Border Patrol formed its Air Mobile Unit in 2003 to monitor remote parts of western California, where tens of thousands of immigrants cross each year.
Increased enforcement in San Diego and El Paso, Texas, has squeezed border crossers into less hospitable corridors, including deserts where hundreds die each year. The Otay Mountains are not the deadliest point along the 2,000-mile border, but they are treacherous.
Dehydration threatens as summer temperatures race past 100; hypothermia is a danger during winter. Broken wrists and twisted ankles are common and it's easy to get lost on the lattice of trails. In the last year, 23 migrants have been reported dead in the Border Patrol's San Diego sector, which includes Otay (pronounced OH-tie).
Given their outdoor office, the agents must be fit.
Mark Cary, a former Marine, once took nine hours to trek seven miles from the dilapidated border fence to the nearest major road, California Route 94. Migrants typically take two days to cover the same route, he says.
All but two of the Air Mobile Unit's 54 agents are men. All but one is under 40 years old — and he's a supervisor with a desk job.
One recent evening, two agents broke thick sweats as they sped downhill over granite boulders and branches burned during California's 2003 wildfires.
About an hour later, one agent pointed excitedly to the right, stepped off the narrow trail, clutched his rifle and peered through the dense brush. Within moments, 14 Mexicans were in U.S. custody.
The agents' shift began shortly before sunset at San Diego's Brownfield Municipal Airport, where nearly every night Black Hawk helicopters take agents into mountains where one canyon is known among migrants as "La Espina del Diablo" — the devil's spine — and trails are named Dead Cow and Tequila Draw.
Just outside Dulzura, a hamlet about 25 miles east of San Diego, Cary and fellow agent Jeff Mielke struck out on one of the countless footpaths blazed by migrants.
Words were few and flashlights were kept off to avoid drawing attention. Midway down the canyon, the agents found the 14 migrants — abandoned by their guide — resting on rocks near one of the makeshift shrines scattered along the border.
The shrine — a cave-like boulder formation just over a mile from Mexico that can fit one squatting adult — contained three burning candles, dozens of extinguished candles and hundreds of prayer cards. One card bore Santo Toribio Romo, the Mexican patron of migrants.
"You're all illegals?" Cary asked in Spanish, as he emptied backpacks of tuna cans, water jugs, pills and prayer cards and frisked each person for weapons. Several nodded yes. Cary said everyone was under arrest.
Jose Ambrosio Ruiz, a 23-year-old construction worker who was headed to Los Angeles, said the group had been waiting near the shrine for four hours.
"I'm tired," said Ruiz, who flew the night before from southern Mexico to the border city of Tijuana. He was to pay his smuggler $1,500 when he arrived in Los Angeles.
The agents used white plastic bands to tie the wrists of 11 men into pairs or threesomes to prevent them from running. A 41-year-old woman and her teenage daughter and son were allowed to walk untied.
The Mexicans walked quietly, occasionally cracking jokes but mostly keeping to themselves.
With one agent leading and the other behind, they walked six hours over moonlit rocks and scrub. During their only rest stop, an agent passed around beef jerky and water.
As the migrants turned uphill on a switch-back trail around 10 p.m., the 13-year-old boy began to limp. He collapsed on the trail every five minutes, muttering "I can't" in Spanish.
Cary sighed in exasperation.
"You play soccer. ... You walk to school," he told the boy. "This is nothing."
Another group of agents in the same canyon called periodically by radio to report their arrests — first a group of 15, then eight, finally two.
At midnight, the agents converged near three vehicles, which took the migrants to a Border Patrol station for interviews and processing. Back at the airport hangar, the agents calculated that they walked 4.2 miles over eight hours, dropping 2,900 feet in altitude and then climbing 200 feet.
All told, the two teams arrested 64 people, adding to the unit's total of about 16,000 to date.
Typically, nearly all migrants return voluntarily to Mexico without facing charges, escorted in vans to the main border station at the Tijuana-San Diego crossing. This night is no different.
One Mexican had been deported three times before. Another said he was a foot guide for the smugglers and was to be paid $200 a person. Neither met federal prosecution guidelines.
"That's what's so demoralizing," said Chuck Albrecht, the Air Mobile Unit's field operations supervisor. "You know a lot of them are just going to try again eight hours later."