At the camp we hunt squirrel out of used to have some Black Phase Grey Squirrels back a few years ago. I got one and gave it to a friend. He was going to mount it in a display he was making, Grey, Fox, and black squirrel.
In the late 1970's an area in the eastern mountains of West Virginia where I worked there was a few Black Phase Fox Squirrels. In sunlight you could see a red hair here and there. My oldest sons first squirrel was one of these Black Phase Fox Squirrel. Later in the season we saw like a family of six young squirrels in one hickory tree. We watched them and left them for seed. Just took grey squirrel for the pot.