I have owned many bird feeders over the years. I always get ones that are constructed with metal parts. The red squirrels managed to get inside my cage feeder and chew up the seed port. Squirrels have no problem chewing through plastic.
The gray squirrels couldn’t get through the cage, but they tried chewing through it.
Gray squirrels can walk along a tightrope with ease. but I don’t think red squirrels have this skill. To protect my expensive feeder, I suspended it on a cable between two trees. At the time of the posting, it is entirely squirrel free.
I chose a different approach for my suet feeder and barn feeder. I heard that a slinky on a pole would provide complete and total squirrel protection.
I watched with amusement as a gray squirrel attempted to climb the pole and was taken to the ground by the slinky. I savored the thrill of victory over these mammals.
That victory was short-lived. I don’t know how but I lost this round.