I grew up with squirrels both red and gray. The red squirrels were the smaller of the two, and their movements were so jerky and birdlike that they made me laugh.
Then I spent a little over a year outside of Philadelphia, Pennsylvania. And was startled to encounter squirrels so dark in fur coloring that they appeared black. Never saw black squirrels anyplace else.
Austin, Texas is positively alive with squirrels, but they are all greyish-brown.