My sister's neighbor used to feed squirrels a lot. Then he got sick and had to spend a couple of months in a hospital and nursing home to recover, thus the squirrel's food supply was cut off while he was incapacitated. When he was finally able to come home he found his redwood picnic table had been chewed nearly in half by the squirrels looking for the corn he was no longer putting out. The table was so damaged it had to be thrown away.
I have been feeding the birds all spring and summer and early on the squirrels found the feeder and worked really hard at getting to it. I had to resort to moving it further from the deck railing so they had a harder time leaping to it. I also had to smear Vaseline on the pole. Funny to watch them leap to the pole and land but be unable to get a grip and just slowly spiral down the pole to the ground! They continued to leap from the deck railing anyway (10 ft away) but instead of trying to land and hang on, they were just bouncing off of it. I thought it funny at first, but then realized it was a deliberate move to attempt to knock the shepherd's hook pole over (it is in concrete, so fat chance of that happening, but they don't understand that). They just keep banging away at the top of the pole and caroming off to land on the ground and then climb up on the deck railing to do it again.
I felt sorry for them and began to put some seeds out just for them... but of course the birds don't know that, but since those seeds are easier for many birds to get to them at once (the feeder has only 4 perches) they eat those first before going to the feeder on the pole! So the squirrels are still not getting their "fair share".
It was fairly easy to squirrel proof the hanging feeder (since I moved and greased the pole they have not been able to get food from it), but trying to bird proof a squirrel feeder is proving much more difficult. I was working on a design for doing that when my sister told me about her neighbor's experience and I have been putting less and less bird seed out in the open for the squirrel to get to. I do worry a bit about the squirrels chewing up the wood railing on the deck, but I would love to see them try to eat my STEEL picnic table!
One of the squirrels did sort of "get back at me"... I have a vial type rain gauge that is on the top of a short post that I stuck into a section of chain-link fence near the deck so I can read and empty it. The post it is on has an LED light in the center of the pole that changes colors for a few hours after the sun goes down, the battery having been charged by the solar cell at the base of the pole. Well... I should say that it USED to light up and change colors at dusk...
One of the squirrels tried to use the solar panel as a launching platform for a leap at the pole feeder and broke it off. This left the small oval panel dangling by the wire up to the LED. This was not bad because it positioned the solar cell to catch more of the evening's sun since it was then hanging down instead of sticking out horizontal. But a month later I watched as one of the squirrels climbed up the fence and began to wrestle with the solar cell. It crawled all over it and curled its body around it and flopped around for a couple of minutes while biting at it. I then noticed something fall to the ground and bounce and the squirrel sort of froze and looked astonished at what had happened. Then it climbed down the fence and picked up the solar panel and, holding it way up high in its mouth, it scampered off to my neighbor's yard where I lost track of where it went.
And I caught it all on one of my surveillance cameras! I doubt if anyone but me could figure out what was happening since it is too far from the camera to make out much detail, but since I know what was on the fence and what is missing now I can see it well enough to know that is what happened.
Kleptomaniac squirrel!