By FERNANDA SANTOS, The New York Times
Published: August 2, 2013

ARIVACA, Ariz. — Monsoon rains tinge the desert with deceptive hints of green at this time of the year, but migrants crossing illegally from Mexico continue to risk death from thirst and exposure in the blazing heat. A fortunate few who become lost might stumble upon lifesaving gallon jugs of drinking water, scattered by a band of volunteers along makeshift footpaths that have been carved through the mountains and washes.

From a primitive base camp here, volunteers trained by a group called No More Deaths patrol the desert, offering water, food, clothing and medical care to lost, injured and exhausted migrants, no questions asked. The group’s mission is as simple, though not uncontroversial: to end migrant deaths along Arizona’s borderlands.

On average, 144 gallons of water a week are carried out of the camp, where bathrooms are buckets equipped with toilet seats, and bedding is a sleeping bag stretched out on the dirt.

Byrd Baylor, 89, a best-selling children’s book author living on 35 acres here, had been helping migrants “get to where they need to go” for years, she said, by distributing food and water to those who crossed her land. A decade ago, she gave permission to No More Deaths to set up a base near her home — because, she explained, “we were all doing the same thing, more or less.”

For Ms. Baylor, helping migrants is an organic part of living in a remote corner of the desert. For the organization’s volunteers, it is serious business. The group, co-founded by a Presbyterian pastor whose church served as a sanctuary for Central Americans fleeing bloodshed in the 1980s, is made up of volunteers, mostly white and largely progressive, who are quick to criticize the intense focus on security at the border. Questions of citizenship and legal status seldom dominate the discussions here; compassion, they say, is their motivation.

“This is not about immigration,” Emrys Staton, 31, a volunteer since 2004, said one recent morning as he and four others traversed a wash. “It’s about saving lives.”

Summer is the deadliest season here, with its oppressive heat, and rivers can surge unexpectedly, sweeping away anyone trying to cross. Poisonous scorpions and rattlesnakes lurk. Loose rocks underfoot can cause a deadly tumble into canyons or crevices.

The group’s methods are meticulous, and Byrd Camp, as the base is known, functions as its launching pad.

Planning for the day begins the previous night, after the group shares a communal dinner that can be surprisingly tasty, like the curried garbanzo beans cooked by Mr. Staton, or simply a surprise, like the vegetarian lasagna that arrived unexpectedly on a recent Wednesday, donated by a church in Tucson.

Over the years, the group has mapped dozens of routes, bushwhacking through hills and valleys in search of hidden paths carved by migrants.

“Do you want to discuss a wake-up time?” one of the volunteers asked one night.

By 6 a.m. on Thursday, another volunteer was walking past the group’s camping tents, strumming a guitar and singing random lines from Taylor Swift songs.

By 7:30, the volunteers were traveling to water distribution points by car and by foot, breaking for a lunch of peanut butter sandwiches under a mesquite tree. At each drop spot, they counted the jugs they found: untouched, consumed and vandalized. There was speculation that some of the containers may have been damaged by Border Patrol agents, who have been caught on film dumping the water the volunteers have left behind.

In a statement, Customs and Border Protection, the Border Patrol’s parent agency, said that the agency did not tolerate misconduct, and that agents were appropriately disciplined whenever it was identified. The agency conducts “ongoing dialogue with humanitarian groups,” the statement said, and despite their different missions, “both sides are committed to reducing deaths in Arizona’s harsh desert environments.”

The Border Patrol has placed rescue beacons and warning signs in the desert, and broadcasts messages in Spanish across the border in an effort to discourage border crossers. Its elite search-and-rescue team often comes to aid migrants, like the nine Mexicans abandoned by their smuggler near Arivaca late last month, one of whom died before help arrived. (Later, the survivors were processed for deportation.)

No More Deaths volunteers recalled a time when border agents were sometimes stationed on a hill overlooking their camp, which migrants were likely to stumble upon if they followed a wash named Papalote. In 2009, some volunteers who were depositing water along a route through the Buenos Aires National Wildlife Refuge were stopped by Border Patrol agents and cited for littering by another federal agency, the Fish and Wildlife Service. One man contested the charge before the United States Court of Appeals for the Ninth Circuit, and in 2010, a panel of judges ruled, 2 to 1, that jugs of water were not garbage.

During a training session for new volunteers in Tucson last month, Maryada Vallet, a longtime member of the group, made its position clear. “We’re not there to sneak anything by the Border Patrol,” she said. But she emphasized that the Border Patrol was to be called for help only if a migrant requested it.

On the trails here, signs of migrant traffic can be found everywhere: an abandoned sneaker with a piece of carpet stapled to its bottom to prevent footprints; jugs of water made of black plastic, so that they do not reflect sunlight; empty packets of Isadora Bayos Frijoles, a Mexican brand of refried beans that travelers have carried for food.

Maggie Duffy, 21, an anthropology major at Notre Dame who was volunteering for the first time, spent part of one recent day reading coordinates from a GPS to Lydia Delphia, 21, as she steered a beat-up Dodge Ram known as Godzilla (because “it’s big and bad,” Ms. Delphia said) to trailheads west of Byrd Camp.

Another first-time volunteer, William Berk, a medical student at Brown, picked up the task in the afternoon. He played a Yeah Yeah Yeahs song on his iPhone as the truck rumbled on.

Volunteers must apply to spend time at Byrd Camp, which is usually staffed by no more than 10 at a time. This summer, at least 85 did, most of them college students, said John Warren, 53, a No More Deaths veteran who coordinates camp staffing.

Ms. Duffy arrived in the desert to volunteer after spending a semester abroad, first on a raspberry farm in the Chilean countryside, and then in the country’s capital, Santiago. She learned about No More Deaths during her sophomore year, in a border-studies course that included visits by the group and other humanitarian organizations.

Mr. Berk, 25, said he discovered the group while searching for work that would get him out of the Brown library, where he had been writing papers about H.I.V. policy. He is thinking about working for a humanitarian medical organization someday, and hoped that his experience at the camp would offer a taste of that.

“Mountains all over,” he whispered as he walked through a thicket of thorny bushes.

“My life is a lot of adults telling me what to do,” Mr. Berk said, spreading his long, lean arms, like a bird in flight. “Here, it’s us, making it happen.”

More Photos