Why did the Oneida tribe choose to fight for the Patriots?

The Oneida were part of the Iroquois Federation, an alliance of six tribes: Cayuga, Mohawk, Oneida, Onondaga, Seneca and Tuscarora in what is now New York State. Four of the six decided to support the British, thinking that the British, despite two centuries of injustice, were more likely to honor tribal land claims that had been previously recognized by the the King and Parliament (e. g. Royal Proclamation of 1763). A key leader of this group was the Mohawk chief Thayendanegea, aka Joseph Brant, who had been educated in England and was close to the family of the British superintendent of Indian affairs. He had fought with the British at the Battle of Lake George during the French and Indian War. The British agents also had more resources than the Americans with which to bribe tribal leaders in return for support.

The other two tribes, the Oneida and Tuscarora, decided to support the Americans, largely due to the efforts of the American Indian agent James Dean and a Presbyterian missionary Samuel Kirkland. The opposing tribes made war between themselves as well as against the American and British militaries and the civilian population. The most prominent battles involving the tribes were at Fort Stanwix and Oriskany, and at Bennington and Saratoga.