They were wiped out largely due to smallpox, which they had no immunity to, and wouldn't be cured until 1796. A lot like how most of Europe was wiped out by the Black Death a couple centuries earlier.
ACTUALLY, MY ANCESTORS MIGRATED FROM SIBERIA ACROSS THE BERING LAND BRIDGE. HUMANS ARE NOT A NATIVE SPECIES TO THE AMERICAS; OPEN-BORDERS LEFTISTS:; WE FOUGHT AND STOLE EACH OTHER'S LANDS FOR THOUSANDS OF YEARS PRIOR TO THE ARRIVAL OF THE WHITE MAN