Spawn out of a rear vehicle base at least four sectors from any action. Drive up to a clump of trees and turn off your engine. Sit in a position to where you can see the trees without moving your views. DO NOT!! I REPEAT, DO NOT GET IN THE TURRET!!!! Don’t move your views or interact with the game at all for ten minutes. Don’t even type or bump your mouse (actually it is best to lock your mouse in place with the “h” key). Just sit and wait. After about ten minutes you will start to see little squirrels move around. Try it, it’s cool. The latest patch added light brown and dark brown squirrels. They used to only be black.
P.S. This usually works best if you spawn North or Northeast for some reason. I thinks it’s a bug actually.