Has any other squirrel hunter noticed this?
I have lived in the deep south and also the far north and have always had a yard full of Gray squirrels around the bird feeders - and the Florida grays are very noisy - sounding almost like a cat whenever any animal or person goes into the yard - they are constantly raising cain about something. But these Northern grays are (so far) almost totally silent. I've had as many as 6 at a time in my yard here in Vermont and have yet to hear one make a sound, and when I tried out my old squirrel call that worked like a charm on the Florida squirrels, These Northern ones either ignore it or freak out and run off.
They sure look like the same squirrel. Just seems kind of strange to me.