A near perfect bird feeder is Gardeners Globe Cage Feeder and Mixed Seed Globe Cage Feeder (see picture below).
The problem with these feeders is they only let small birds enter. Another problem is that California squirrels apparently are very intelligent. “My” squirrels can unscrew the lid and get to the inside top of the feeder.
I decided to lock the top lid into its closed position. I did this by drilling a carefully positioned small hole for a small screw to be put in and lock the lid. If you decide to improve this bird feeder and also wish to drill this hole make darn sure that the lid is turned to be locked so the holes line up properly. Do not drill anywhere close to the wires.
“My” squirrels now need to get a Phillips screw driver and learn how to use that tool to unscrew this bird feeder and get to its treasure.
I conditionally recommend these feeders. You could start out to see the intelligent level of “your” squirrels. If they are low wattage light bulbs, you may not need to drill a lock hole.