In 2004 to 2006, more than 1,200 vehicles with an estimated value of $33-million, were hauled away from the reserve. In 2007, at least 578 were recovered. This year's tally so far exceeds 80.
And because the 18,000-hectare reserve - an hour's drive west of Toronto and home to the protagonists in the long-running Caledonia land-claim tussle - is so thickly forested, the real numbers are probably higher still.
The Ontario Provincial Police rarely ventures on to the reserve without the approval of its 28-officer police force.
"Some cars stay buried in the woods for years," said Detective Constable Wesley Barnes of the OPP-led joint forces auto-theft team, recently joined by the Six Nations police. "If you gave me a helicopter and the time, I could find you a hundred stolen cars."
Spirited away from hotels, train stations and other spots from across Ontario's Golden Horseshoe, the stolen vehicles are most commonly dumped at night. And like the Hummer and the Avalanche, the targets of choice are high-end pickup trucks and SUVs made by General Motors.
Mostly they are stolen for their parts. Discovered the next morning - if they are discovered - they have usually been stripped of their wheels and other fixtures and sometimes torched.
Talk to police both on and off the reserve and they will tell you that, like everywhere else, a sizable proportion of the thieves are juveniles who face little or no jail time. And as also happens elsewhere, drugs appear to play a part in fuelling the trade in hot car parts - in particular, demand for the prescription painkiller Oxycontin.