If you can sneak into a stand of oaks or hickory tree that squirrels are cutting nuts in they work great. I am referring to the Mr. Squirrel call.
Once you are in place start making the distress call with bow ready. The red fox will usually come right down the tree barking at you. Most shots are feet not yards away.
It is not unusual to be able to call them back after a miss for another shot.
The key is to sneak in without being detected before calling. If you are blowing the call right birds, crows, and sometimes coyote will come to the call.
If I do not get the squirrel to come from calling I will then shake a nearby sapling while calling and they usually come tearing down the tree to see what has a hold of one of their buddies. Wear camo and mask.
Grey squirrels don’t seem to respond as well. I have called up to 5 squirrels from one setup. They came from several different trees and one came from about 50 yards through several trees.
It's a blast! Take plenty of arrows!