When we moved in this house almost a decade ago, the previous owners had a feeder on a 4X4 post in the yard. The squirrels would empty it out pretty quickly.
Now, I don't mind if they want to police up the stray sunflower seeds that the birds dropped, but I'm not paying to feed the squirrels.
I got a small and inexpensive fence controller and ran the output wires up the pole, bare copper house wire spiraling up from the bottom keeping them an inch apart.
There was a learning curve as they at first tried to climb the post like normal, only to get a robust electric jolt that would send them flying. They tried a hundred ways from Sunday to get up that pole, and now almost ten years later they never even try. A youth trash panda tried once and let out a scream and never tried again.
EDIT to add: Ironically, I noticed the fence controller finally gave up the ghost a few days ago. Not sure if I'll replace it.