As hundreds of migrants line up along an Arizona border wall around 4 a.m., agents try to separate them into groups by nationality.
“Anyone from Russia or Bangladesh? I need somebody else from Russia here,” an agent shouts and then says quietly, almost to himself, “These are Romanian.”
It’s a routine task for the Border Patrol in the wee hours in this flat expanse of desert where the wall ends.
Migrants from at least 115 countries have been stopped here in the last year, but that may be less striking than what’s missing: Mexicans are virtually absent.
Instead, families from Venezuela, Colombia, Haiti, Cuba, Brazil, India and dozens of other countries arrive in Yuma after wading through the knee-deep Colorado River.
Their presence reflects how a pandemic-era rule still shapes the journeys of many migrants, even though much of the U.S. has moved on from COVID-19.
The changing demographics mark a dramatic shift away from the recent past, when migrants were predominantly from Mexico and Central America’s Northern Triangle countries — Guatemala, Honduras and El Salvador.
That’s especially clear at some of the busiest crossings, like Yuma and Eagle Pass, Texas, near where several people died in recent days while trying to cross the Rio Grande.
Mexicans still cross elsewhere but often try to elude capture because they are likely to be expelled under a pandemic rule that denies them a chance to seek asylum.
Mexicans still account for 7 of every 10 encounters in the Border Patrol’s Tucson, Arizona, sector, where smugglers order them to walk at night with black-painted water jugs, camouflage backpacks and boots with carpeted soles to avoid leaving tracks in the sand, said John Modlin, the sector chief.
“Incredibly different tale of two borders, even though they’re within the same state,” Modlin said.
Migrants who are not from Mexico and the Northern Triangle accounted for 41% of stops on the border from October through July, up from only 12% three years earlier, according to government data.
In Yuma, they wear sandals and carry shopping bags stuffed with belongings over their shoulders.
Some carry toddlers.
The migrants typically walk a short distance through tribal lands and surrender to agents, expecting to be released to pursue their immigration cases.
Meanwhile, Mexicans made up 35% of all border encounters from October through July, higher than three years ago but well below the 85% reported in 2011 and the 95% at the turn of the century.
In theory, the rule that denies migrants the right to seek asylum on grounds of preventing spread of COVID-19 applies to all nationalities.
But in practice, Title 42 is enforced largely for migrants who are accepted by Mexico, which agreed to take in people expelled from Guatemala, Honduras and El Salvador, as well as its own citizens.
It is difficult for the U.S. to send others to their home countries due to costs, strained diplomatic relations and other considerations.
“The challenge is what Mexico can accept,” Modlin said. “That’s always going to be a limiting factor.”
In Yuma, Title 42 has become almost nonexistent, with the pandemic rule being applied in only 192 of 24,424 stops in July — less than 1%. In Tucson, it was used in 71% of stops. A court order has kept Title 42 in place indefinitely.
It is unclear why routes are so divergent. U.S. officials believe inhospitable mountains and canyons near Tucson favor people trying to escape detection, while the ease of crossing in places like Yuma makes those paths better suited for families seeking to surrender.
“What we know with absolute certainty is that the smuggling organizations control the flow,” Modlin said. “They decide who goes where and when they go to the point. It’s almost like air traffic control of moving people around.”
In Yuma, groups of up to about two dozen migrants are dropped off by bus or car on a deserted Mexican highway and then begin arriving shortly after midnight at the edge of the imposing wall built during Donald Trump’s presidency.
If English and Spanish fail, agents use Google Translate to question them under generator-powered lights, take photos and load them onto buses.
Migrants arrive over several hours on different paths, sparking concern among agents that smugglers may be trying to confuse them to sneak some through undetected.
One recent morning, six Russians said they flew from Istanbul to Tijuana, Mexico, with a stop in Cancun, and hired a driver to take them four hours to the deserted highway where they crossed.
A 26-year-old man who flew from his home in Peru to Tijuana said the most difficult part of the journey was the anxiety about whether he’d make it to his destination in New Jersey.
Nelson Munera, 40, said he, his wife and their 17-year-old son got off a bus on the highway and crossed to Yuma because fellow Colombians had taken the same route.
Lazaro Lopez, who came with his 9-year-old son from Cuba by flying to Nicaragua and crossing Mexico over land, chose Yuma because that’s where his smuggler guided him.
“An opportunity presented itself,” said Lopez, 48.
The Border Patrol drops off hundreds of migrants each day at the Regional Center for Border Health, a clinic near Yuma that charters six buses daily to Phoenix Sky Harbor International Airport.
Migrants are released on humanitarian parole or with a notice to appear in immigration court.
The clinic began the airport shuttles for migrants in February 2021 and recently added buses to Washington, paid for by the state of Arizona.
“We have seen families from over 140 countries,” said Amanda Aguirre, the health-care provider’s chief executive officer. “We haven’t seen one from Mexico, not through our processing.”
The shift is also evident on the Mexican side of the border.
The Don Chon migrant shelter in nearby San Luis Rio Colorado fills many of its roughly 50 beds with Central Americans who were expelled under Title 42.
Kelvin Zambrano, 33, who arrived in a large group of Hondurans, said he fled threats of extortion and gang violence.
Border Patrol agents wouldn’t let him share his story, he said.
“I don’t know why, but they don’t want Hondurans,” he said.