Cattleman Joe Harris is on the frontline of a Wild West showdown between Cowboys and Mexicans.

He says the hundreds of illegal Mexican immigrants that cross his border ranch every day leave a trail of destruction that threaten his way of life.

Rancher Joe Harris says the migrants harm his cattle

"A lot of them bring garbage bags," Mr Harris says. "They use them to sleep in or as makeshift rain ponchos."

"Cattle, for whatever reason, pick them up, chew on them. They get in their stomachs and plug them up, and the cow will actually starve to death," he adds.

Gunpoint detention

Regarded by some as a vigilante, Joe's neighbour Roger Barnett has gained notoriety by detaining the Mexicans he finds on his land - sometimes at gunpoint. But is he ready to shoot?

"You betcha. If they threaten me or my family in any way with bodily harm, they would probably be bought and paid for," he says.

"What does bought and paid for mean," I ask.

"I would exert enough force to protect myself and my family," he adds.

Border watch

Anywhere and anytime in this part of southern Arizona you'll see illegal immigrants being arrested, the huge numbers involved have the ranchers describing it as an invasion.

The border patrol use infrared cameras to track migrants

Physically, the problem is easy to understand. A barbed wire fence is all that separates the US from Mexico.

The US Border Patrol arrest up to 50,000 migrants a month in this area, and most locals say almost four to five as many are never caught.

With men and machinery the US border patrol is making a stand in Douglas. At dusk, agents can see would be immigrants just a few feet away, waiting for darkness for their dash to America.

At headquarters, infrared cameras are used to direct agents in the field to the unsuspecting Mexicans.

It's a job and a fight that the US border patrol says the ranchers should stay out of.

"Leave the law enforcement aspect to law enforcement," says Alfredo Esquivel with the US Border Patrol.

"If there are people you see on your property, call either the police department or call border patrol."

Gun-toting tradition

In Arizona there's a tradition of gun-toting justice.

Arizona has a tradition of gun-toting justice

The Wild West's most famous showdown the gunfight at the OK Corral is re-enacted here on a daily basis.

Audiences love it, but it's a tradition of justice the Mexican Government says is dangerous in the hands of 21st century cowboys.

"These apprehensions are being made with a show of force," says Mexican Consul Miguel Escobar, adding the private citizens apprehending migrants are carrying either side arms, shot guns or rifles.

"We believe that these migrants are being intimidated and their human rights are being violated."

But in the Douglas the mass migration goes on for another night: the lure of better jobs in America set against the ranchers' love of their land.

It is an explosive mix that now threatens this remote corner of the old Wild West.