I'm still trying to reconcile what I'm seeing on the ground and what I'm reading. There seems to be a lot of discrepancy.
No Fox Squirrels here, but some Reds nearly as large as a Fox. They say the Grays are larger than the typical Reds, here they are a lot smaller. At least that is what I'm seeing in my area.
Grays were protected, but now they say they are an invasive species?
Best guess is Squirrel studies have a long ways to go to be reliable. Regional differences can be profound. And there may be some inter breeding.
I've got a Red Squirrel that hangs around my garden now that is way larger than what is published as normal. And a smaller Red with a large brindle stripe down it's back.
I was reading and they are saying the decline in the Red Squirrel population is from a virus endemic in Gray Squirrels that the Grays are immune to. But they say the Reds are making a come back. Best guess is the surviving Reds also have some immunity and are passing it on to their offspring.