Patterns of migration can change frequently along the border, which means some agents are overwhelmed by the amount of work they have to do while others have time on their hands.
"There's a big mismatch," AP reporter Elliot Spagat tells Take Two. "South Texas has been the big hotspot."
That's where a rise in unaccompanied minors, mostly from Central America, has strained resources in the region.
For example, Texas' Rio Grande Valley has had a surge in arrests — nearly 200,000 since last October — but more border patrol agents are stationed in Arizona, which has had just 72,000 arrests during that same period, said Spagat.
To help balance the work flow, authorities are employing some new techniques, relying on webcams to talk to those apprehended at the border. The technique offers advantages in terms of using limited resources and reducing cost, but could also come with drawbacks.
"There's definitely something lost in not speaking to someone in person," said Spagat, noting that the practice is typically not used in criminal cases.