Long stretches of silence on a Border Patrol scanner are punctuated with updates on tracking a single migrant for hours. The radio traffic sounds like a throwback to earlier times, before the United States became the largest destination for asylum-seekers in 2017.
President Donald Trump's declaration of a border emergency comes at a time of relative calm after years of deep turmoil. Active-duty military arrived Thursday in San Diego and in El Paso, Texas, as part of an initial deployment of 1,500 troops.
Arrests for illegal border crossings plummeted more than 80% to about 47,000 in December from an all-time high of 250,000 the same period a year earlier. Arrests fell by about half when Mexican authorities increased enforcement within their own borders a year ago and by about half again when former President Joe Biden introduced severe asylum restrictions in June.
The job of a Border Patrol agent has changed dramatically in recent months, away from quickly processing and releasing asylum-seekers with notices to appear in immigration court. Agents are returning to a more traditional role tracking individuals and small groups trying to elude capture.
Many agents chafed under Biden as arrests topped 2 million for two straight years, though traffic slowed sharply before Trump took office on Monday. The Border Patrol released fewer than 7,000 migrants in the U.S. in December, down 96% from nearly 192,000 a year earlier.
In San Diego on Thursday, agents focused on an area of deceptively treacherous mountain trails with expansive views of Tijuana, Mexico, its urban sprawl and industrial warehouses in San Diego. Migrants who elude capture walk as long as two days in the wilderness before arriving at smugglers' vehicles.
Since Trump took office, there has been a noticeable decrease in migrant activity, possibly due to freezing temperatures and wildfires. Arrests in the San Diego sector plunged to an average of 236 a day during the last week of Biden's presidency, from more than 1,400 a day in April. Wednesday's arrest tally was 136.
Trump's orders will hinge on how he pays for detention and transportation, as well as how he manages countries that won't take back their citizens. During his first term, he used emergency powers to divert billions of dollars from the Defense Department for a border wall.
In Arizona, Pima County said Thursday it was closing two migrant shelters in Tucson because the government has stopped releasing people to them. Since 2019, the county had sheltered more than 518,000 migrants.
Jewish Family Service of San Diego said its shelter had not received any migrants since the Trump administration ended use of the online border app, CBP One, for migrants to legally enter. It served 791 people the week before Trump took office.
