Border agents, traffickers and migrants mix on busy Rio Grande in US

Migrants from Central America, who arrived illegally from Mexico to the US to seek asylum nearly tripled in February from a month earlier to about 19,000 people. Hunger and poverty are spurring their flight. So is disinformation that has rocketed across social media and by word of mouth that the US border is now wide open.

Let's take a look:

US Customs and Border Protection (CBP) continues to enforce a policy, implemented by former President Donald Trump one year ago, of returning most southern-border crossers to Mexico.

About 70,000 people, or 72 per cent of such migrants - mostly single adults - were rapidly deported in February alone, according to CBP data. Some of those people were likely repeat crossers as the recidivism rate has climbed in the past year, according to US officials.

"Don't come over," Biden said in a March 16 interview with ABC News when asked to articulate his message to hopefuls. "Don't leave your town or city or community."

Still, it's true that more migrants - mainly children and families - have been allowed to enter the United States in the early days of his administration than in the final days of Trump's.

In February, more than half of the family members caught with children at the border were not expelled. Many have been released from CBP custody into the United States as they await asylum hearings.

Their success has supercharged migrant and smuggler communication channels, with many now urging travelers to head north before the door slams shut, said Andrew Seele, president of the Migration Policy Institute, a nonpartisan Washington-based think tank.

Since January, the State Department has placed more than 28,000 radio ads in Spanish, Portuguese and six indigenous languages on 133 stations in Guatemala, Honduras, El Salvador and Brazil, and it has worked with Facebook and Instagram to create advertisements to dissuade migrants, according to the department and the White House.

Whether it works remains to be seen. Trump's anti-immigration message was loud and clear. Yet on his watch in February 2019, U.S. border agents encountered more than 40,000 people traveling in family groups, about twice as many as the Biden administration saw last month, according to CBP figures.

Biden, in a shift from the previous administration, said he would not turn away "unaccompanied minors", kids crossing the border without parents or legal guardians. These children can now enter the United States to pursue asylum claims, in accordance with US law.

The new administration has done the same for some migrant families along a limited, 230-mile stretch of the border between Texas and the Mexican state of Tamaulipas. That shift came in early February after Tamaulipas refused to continue allowing US border officials to expel back into the state Central American families with children under the age of six. Biden has said his team is working to convince Mexico to take more of those families back.

Much of this nuance has been lost in Central America, a region desperate for an escape valve. Migrants are being driven by gang violence and poverty that has been exacerbated by job losses from the COVID-19 pandemic.

The situation is particularly dire in Honduras, where hurricanes Eta and Iota last November destroyed tens of thousands of homes. Nearly a third of the country's population is now beset by a worsening hunger crisis, according to a government report published in February.