They already moved because of the threat from the Settlers.
Explanation:
Florida was a very popular region among the settlers. This territory possess a perfectly warm climate and excellent soils that make it easy to grow various types of crops.
This made a lot of people move here to opened up plantations/farms. As the number of settlers increased, Native Americans faced bigger threats of engaged in the conflict /being killed. This forced them to spread out and move to other territories before the creek migration even began.
