Sciurus niger, a large tree squirrel native to much of the eastern US, was introduced in California in the early 1900’s. Our native Western Gray Squirrel prefers large areas of contiguous forest while these Fox Squirrels are more ecologically flexible and willing to occupy human dominated landscapes.
For more info: https://baynature.org/2019/05/28/are-fox-squirrels-replacing-gray-squirrels-in-california/
