Mike,
I feel your pain
I have 2 feeders the same as the lower one in your photograph.
A few days ago I noticed a squirrel upside down on one of them. When he was finished exploring the feeder he had big trouble climbing back up the wire it hangs from. It was comical! Kay and I laughed a lot as he tried to climb up and slid back down repeatedly.
We laughed even more as a large red-shouldered hawk made a pass at the squirrel, hitting the wire as he went by and kept going, The squirrel, now extremely motivated, made it up the wire in record time. We laughed a lot over that sequence of events.
The next day I discovered why I shouldn't have laughed. I noticed the feeder was totally empty. I lowered it and turned it over. This is what I found:

- Feeder hole 1.JPG (3.24 MiB) Viewed 11825 times
The bugger had chewed a hole in the bottom allowing all the seed to dump on the ground for him and his buddies to scarf up!
I'd seen that hole before: about six months ago the other feeder looked the same. I chalked it up to 6 years in the Florida weather and got a new seed tube from the manufacturer under their warranty. It is now plain as day that one suffered the same (chewing) fate as this one.
Out of curiosity I looked at the other feeder and found this:

- Feeder hole 2.JPG (3.6 MiB) Viewed 11825 times
It's now obvious that work had begun again on the feeder with the new seed tube.
So now it's the human's move. I made hardware cloth screens and put them below each feeder's seed tube. Here's what they look like:

- Feeder bottom screen.JPG (3.48 MiB) Viewed 11825 times
I refilled the feeders.
Squirrel's turn...