A number of policy changes and shifting migration patterns have caused the number of migrants to spike to unheard of levels in 2021, although the root causes are nothing new, according to experts.

According to statistics from US Customs and Border Protection (CBP), in March the number of migrant entering the United States rose to the highest level in at least 15 years, with 171,000 migrants taken into custody over the course of the month - 71% more than in February.

In March 2020, the number was recorded as 34,460 - a low number attributed to Covid-19 border restrictions, while in March 2019, 103,731 migrants were encountered. In total, almost 600,000 migrants have been encountered since the beginning of this year.

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In a news conference last month, US President Joe Biden attributed the rising number of migrants to cyclical, seasonal migrations, despite the considerably higher figures in 2021.

Across the country, politicians and experts have given a number of reasons for the rising numbers of migrants. 

In March 2020, the number was recorded as 34,460 - a low number attributed to Covid-19 border restrictions, while in March 2019, 103,731 migrants were encountered. In total, almost 600,000 migrants have been encountered since the beginning of this year.

Earlier this week, for example, Democratic Congressman Henry Cuellar - who represents a Texas district that stretches from San Antonio to the Mexican border - placed part of the blame on the Biden administration's messaging to would-be migrants in Central America.

"The feeling out there in Central America is just very simple," Cuellar said of the border. "It's a speed bump, and once I get past that speed bump, I get in."

A majority of the 96,628 single adults and 52,901 family units encountered by agents in March were denied access into the country under US Code Title 42, which allows the government to restrict entry to people in the country unlawfully.

"Title 52 is being used on adults, but we don't see it," he told local media in Texas. "If there are no consequences, it doesn't matter. People will keep coming."

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In an interview with LPO, Tony Payan said that the number of migrants is higher this year for a variety of reasons, including a shift in how people were trying to enter the United States.

"In the past, we used to see individuals, small groups or even slightly larger groups trying to breach the border between ports of entry, evade Border Patrol and make it to whatever their destination city was," he said. "That's changed. About seven years ago we began seeing more family units, more unaccompanied migrants and caravans of migrants marching through Mexico."

"They actually turned themselves tin. That's something that dogged the Obama administration, the Trump administration and now the Biden administration," he added. "The difference now is that the numbers are much higher." 

They actually turned themselves tin. That's something that dogged the Obama administration, the Trump administration and now the Biden administration

The higher numbers are partly a result of the large number of migrants that were waiting in Mexico, stranded as a result of Covid-19 border restrictions in 2020 or the Migrant Protection Protocols (MPP) - the ‘Remain in Mexico' policy - that were ended by the Biden administration in February 2021.

"All of these things make for a really good spike in so-called encounters," Payan said.

In the US, Payan added, media coverage of the rising encounters has added to already existing public concern.

"Americans generally feel very anxious about the border and they feel the border is out of control. That has been the narrative for a long time," he said. "Clearly, that creates a crisis. It's the numbers, plus the media attention, plus the public anxiety."