Conversation so far:
what can you tell me about the early history of blackfoot?
The Niitsitapi, also known as the Blackfoot or Blackfeet Indians, reside in the Great Plains of Montana and the Canadian provinces of Alberta and Saskatchewan.
when did they reside in the great plains?
By 1200.
what else did they do in those years?
Due to language and cultural patterns, anthropologists believe the Niitsitapi did not originate in the Great Plains of the Midwest North America, but migrated.
where did they migrated from?
from the upper Northeastern part of the country.
how did they adapt to being in the plains?
They moved west and settled for a while north of the Great Lakes in present-day Canada, but had to compete for resources with existing tribes.
what kind of resources they had in those early years?
CANNOTANSWER.

Question: what other tribes were they associated with?
Self-contained rewrite: What other tribes besides the ones at the great lakes were the Niitsitapi associated with?