As the election-year debate over illegal immigration heats up, Maryland National Guard members are preparing to deploy to Texas to help monitor the U.S.-Mexican border.

Two crews from the 29th Combat Aviation Brigade will take high-tech helicopters to the southern tip of Texas in June to provide aerial surveillance to U.S. Customs and Border Protection agents on the ground, Guard officials said Wednesday.

They will watch for illegal immigrants and drug smugglers — "basically, people crossing the border without authorization," said Lt. Col. Michael Whelan, commander of the 1-224th Aviation Security and Support Battalion.

"We can send the images down to receivers on the ground so they can see what we see," said Whelan, a pilot, after a demonstration flight at Camp Fretterd in Reisterstown.

The six-month deployment comes as the presidential candidates debate what to do about illegal immigration and Marylanders prepare to vote this fall on a controversial college tuition break for undocumented immigrants.

As the prospects for comprehensive immigration reform grow ever more remote, the Obama administration has stepped up border security.

U.S. Immigration and Customs Enforcement deported nearly 400,000 illegal immigrants during fiscal year 2011, an agency record.

At the same time, officials noted a decline in unauthorized entries. Agents arrested fewer than 330,000 illegal crossers along the U.S.-Mexican border in fiscal 2011, the lowest number in 40 years. The number of immigrants who died trying to cross the border also fell.

Officials and observers attribute the declines to increased enforcement, advances in technology and a U.S. economy that is no longer so attractive.

The Maryland Guard sent troops to staff observation posts along the border in 2006. The coming mission, scheduled to start June 1, will be its first deployment providing aerial surveillance.

The change in the federally funded mission reflects a recent shift in policy. The National Guard had been providing 1,200 ground troops at a time to assist border agents.

In February, that contingent was scaled back and redirected: The National Guard now contributes no more than 300 troops. They fly helicopters and planes or analyze intelligence about smuggling routes in command centers miles from the border.

Guard members began flying regular patrols over the Rio Grande last month.

Officials said the change, which is expected to reduce costs, was made possible by improved technology.

Six Maryland Guard members will be taking two new UH-72a Lakota light-utility helicopters to the Rio Grande Valley. Each of the helicopters is equipped with infrared vision, state-of-the-art mapping technology, a 40 million-candlelight searchlight and digital video cameras and recorders.

"And we've got radios that can talk to law enforcement and EMS rescue personnel," said Whelan. "So, we'll basically be able to augment law enforcement and Customs and Border Protection without executing law enforcement ourselves."

The Maryland Guard has taken delivery of the first of four UH-72a helicopters to replace its four OH-58a Kiowa helicopters. Officials said the newer aircraft is faster, flies in worse weather, carries heavier loads and stays in the air longer.

Maj. Gen. James A. Adkins, commander of the Maryland National Guard, said the UH-72a is suited to both homeland security and disaster response missions.

"It's perfect for our state mission," he said. "Pilots love it."