They were snowmobile tracks leading out onto the ice of the frozen St. Lawrence River that runs between upstate New York and Canada. At night smugglers race across the ice with bags of marijuana. Pickering shielded his eyes with his hand as the wind covered the tracks; he couldn't see whether they went all the way across the border.
"There are all these islands out here, and the snowmobiles just come shooting across," Pickering said. "It's a constant battle."
This is the United States' forgotten border, where federal agents and police play cat-and-mouse with smugglers and illegal immigrants along 4,000 miles (6,400 kilometers) of a mostly unmarked and unfortified frontier with Canada. Unlike the southern border with Mexico, where drug-related violence has exploded in recent years, the northern border rarely makes headlines.
That changed this month after the U.S. Government Accountability Office released a report warning that the terrorist threat from Canada was higher than from Mexico because of the vast swaths of unprotected frontier. Just 32 miles (52 kilometers) of the 4,000-mile border have an acceptable level of Border Patrol security, with agents available to make on-site arrests, the report said.
Senators from northern border states urged the U.S. federal government to deploy military radar and more unmanned planes. The head of the Senate's Homeland Security committee, Sen. Joe Lieberman, suggested the government should examine whether to require visas of Canadian visitors.
"Our country is so focused on the southern border," said Republican Rep. Candice Miller, of the northern border state Michigan, who will chair a hearing about the report on Tuesday. "At the same time the northern border is essentially wide open."
Drug seizures and crime along the U.S.-Canadian border are nothing compared to what's smuggled across the southern border, said Mark Salter, an expert on national security at the University of Ottawa. Canada's stronger economy and smaller population - about 33 million compared to 147 million in Mexico and Central America - also means there is less illegal immigration.
"There is simply not the scale of threat to the United States from Canada as there is from the southern border," Salter said.
However, recent drug arrests have highlighted the U.S.-Canada border's porousness. In May, a Canadian kingpin confessed to running 2,000 pounds (900 kilograms) of marijuana a week through the forests of upstate New York. A gang arrested in November was charged with smuggling the narcotic painkiller OxyContin. And in December, Canadian officials arrested 29 smugglers on charges of using boats to run tons of marijuana, Ecstasy and methamphetamine across the Great Lakes to Michigan and New York.
President Barack Obama and Canadian Prime Minister Stephen Harper signed a Feb. 4 agreement to share more information on travelers and better coordinate cross-border investigations. The Department of Homeland Security has tripled the number of agents on the northern border in recent years and is building a $30 million intelligence-gathering center at a Michigan Air National Guard base.
Some critics say the Canadian threat is overblown, saying the volume of most drugs seized along its border is still a tiny fraction of 1 percent compared to seizures at U.S.-Mexico crossings. Residents complain that increased patrols are scaring away Canadian visitors.
"There are more drugs on Wall Street than here," said Jonathan Maracle, 35, who owns a gift shop on the 12,000-member Akwesasne Mohawk reservation, straddling New York and Canada on both sides of the St. Lawrence River. "All they're trying to do is make us look bad up here because they can't control up here. The United States government is nothing but bullies."
Few places show the challenges border agents face like the reservation, a frigid archipelago a few miles downriver from where Pickering rode his snowmobile on a recent afternoon, offering The Associated Press a tour of his territory.
About 20 percent of all the high-potency marijuana produced in Canada - "multiple tons" each week - is smuggled through a patch of border less than 10 miles (16 kilometers) wide on the reservation, the U.S. Department of Justice reported in May. Since 2008, U.S. prosecutors say they have broken up four major smuggling rings operating on the Mohawk territory.
The river here is scattered with small islands that smugglers can use for cover as they hopscotch across the border in boats and snowmobiles. Thick forest on both sides provides cover from surveillance planes.
The political landscape is even more complicated than the geography. The Mohawk territory sprawls across both sides of the river and spills into both Quebec and Ontario.
Tribal leaders and police officials declined the AP's interview requests. But two huge signs at a main intersection spell out a common sentiment toward outside authorities threatening the tribe's autonomy.
"Yes, 'terrorists' come thru Akwesasne. They are N.Y.S.P. (state police), Border Patrol, ATF, FBI, etc., etc.!"
U.S. Border Patrol agents rarely go onto the territory without a tribal police escort, said Wade Laughman, agent in charge at the Massena Border Patrol.
"You get a lot of intimidation techniques: blocking in of your vehicles, people yelling at you, screaming at you, guys surrounding you," Laughman said. "It's not safe for one agent to go down there by himself."
Smugglers run contraband in both directions, Laughman said: marijuana, Ecstasy and methamphetamine come south while money, tax-free cigarettes, weapons and cocaine smuggled from Mexico goes north.
One admitted smuggler, Steven Sarti, described to a U.S. judge in May how he and an 18-man crew stuffed high-potency marijuana into black duffel bags used for hockey gear, then coded the bags with numbers representing different buyers. The gang smuggled 2,000 pounds of marijuana a week.
There have been no confirmed cases of terrorists coming through the reservation, but U.S. officials say they're worried it could happen.
"The folks we're dealing with, both in drug trafficking and terrorist activities, are not stupid," said James Burns, who directs Drug Enforcement Administration operations along the New York-Canada border. "We don't want to have anybody exploit a weak point."