The 5 squirrels in 150 yards is just the ones that I can see... There are probably 4 or 5 times as many. This is around our house where they get shot on a regular basis. Sitting out in the woods in a tree stand and the numbers are visibly much much higher.
We have coyotes and a couple species of hawks and buzzards that they are food for. Better they have an easy diet of dead squirrel than rabbit.
Last fall there were 2 hawks that would be drawn by the sound of my 17, easy meals for them I guess. It was kind of cool to go out and target shoot and see them perched up in the tree right above my target.