Rowling's second foray into North American wizarding history touches on the American colonies during Puritan times, delving into literal witch hunts like the Salem Witch Trials. It all began when European Muggles/No-Majs began to make their way to the New World in search of religious freedom — their journey encouraged many European magicians to seek the same sort of fresh start. Some of these witches and wizards sought adventure, while others used the mass exodus of No-Majs as a way to blend in and escape from European wizarding authorities.
Because such a significant portion of these magical European colonists were attempting to flee punishment for past crimes, a need emerged in America for a form of wizarding law enforcement — unsurprisingly, a group of power-hungry and relentless wizarding mercenaries stepped up to fill this void. Rowling describes these wizards, dubbed Scourers, as "an unscrupulous band of wizarding mercenaries of many foreign nationalities, who formed a much-feared and brutal taskforce committed to hunting down not only known criminals, but anyone who might be worth some gold."
With time, says Rowling, the Scourers because corrupt and bloodthirsty . . . they began to dabble in wizard trafficking, and had no qualms with framing innocent No-Majs for "witchcraft" in order to collect a paycheck from frightened non-magical folk. This sort of cruel, manipulative behavior led to some of the most famous witch hunts in history.
The famous Salem Witch Trials of 1692-93 were a tragedy for the wizarding community. Wizarding historians agree that among the so-called Puritan judges were at least two known Scourers, who were paying off feuds that had developed while in America. A number of the dead were indeed witches, though utterly innocent of the crimes for which they had been arrested. Others were merely No-Majs who had the misfortune to be caught up in the general hysteria and bloodlust.
These witch trials discouraged many European wizarding families from emigrating to the New World and caused many who had already made the voyage to flee. Through such circumstances, the wizarding population in America became far smaller than in other continents, with a higher percentage of No-Maj-born witches and wizards in the States. Understandably, this meant that the "Pure Blood" prejudices so prevalent in Europe never caught on amongst American wizards.
Read Rowling's full exploration of the 17th Century and Beyond to learn more about colonial wizarding history and how various trials led to the formation of a magical government.
