There are two huge trees in my yard, but alas, no squirrels. I think the neighborhood dogs must keep them away. When I lived in Missouri near the river there was a large population of squirrels. The largest number I ever saw visiting the feeder in my front yard at one time was fourteen. This included the young ones.
When I lived in Arizona, there were no squirrels anywhere near my home and I frequented a couple of online squirrel cams which have disappeared over the years.