@dosmalo
In a perfect world, where they weren't an attic nuisance,... would they nest in trees? debris??
The ground squirrels dig burrows that can go 4'+ deep, and spread out 12' or so from the entrance, in multiple tunnels leading to different den areas (or so I've read).
I've been removing an old in-ground liner swimming pool. I found a view into a den when I took out the liner.
This is the area just below the den entrance that was below the wood pool deck. The "other side" of the pool liner was a wall to their den, and this is the opened up view of some of it. The black holes to the right of the main tunnel are more tunneling spots.
I have a squirrel den sinkhole (is what I suspect it is) out front in the yard. We call it the Sump. The ground is so soft there that I can hand push a 2' concrete form stake into it, all the way, just by pushing it into the ground, by hand.
We emptied the swimming pool into this sump, 12k gallons, and it never even puddled; straight into the soft soil.
There is another place on my neighbors property where a truck caved in a hole, and it was stuck to its axle.
Destructive?