1. attach the feeder to a narrow pole in the middle of nowhere with no trees over it - failed.
2. squirrel proof feeders that close (shift down) when the weight of the squirrel hangs on it - failed.
3. Bag type metal netted "squirrel proof" feeders - failed.
4. Give up and feed the squirrels and birds - success.
About the only thing I have not tried is the spinning bird feeders ... because 50 bucks is a bit extreme... but I have enjoyed watching the youtube videos of them... most owners note that eventually the squirrels get used to the spin and continue to eat.
I think short of killing all the squirrels, the best you will be able to do is get one with a cage around the feeder that is large enough for birds to get in or stick their heads in but small enough to keep the squirrels out. Even our cardinals and wood peckers have adapted and can get seeds out of our feeder now.
I have had "some" success with a large clear plastic round shroud which tapers around and more than covers the periphery of the top of my bird feeder. The feeder itself hangs down from a hook set in the middle of a large tree branch. The hook goes through the shroud to the top of the feeder.
The "secret" is to first use a good car wax on the shroud, buffed and polished to make it as slippery as possible. This is key to success! However with time and weather, you will have to repeat the waxing pretty much as you would a car!
Fun to watch as they climb down the hook from the branch and as soon as they hit the shroud, slip right off, around the feeder, and down to the ground... at least until the buffed wax sheen lasts.
It's too big to scale, and the internal collar allows it to wobble, further discouraging them. I've never had a squirrel get past one of these. -- The curse and blessing of the human brain is whatever we can conceive, will be done, regardless of the consequences.
I've taken a WD-40 type spray and put it on the poles that the squirrels used to climb up. Now they get up about a foot and then slide down. Their claws just don't grip. Just have to reapply the spray every once-n-awhile. -- »www.caryontech.com
I have a similar feeder to that Yankee one. On mine you can take off the ring and just leave perches. Makes it harder for the squirrel to grab. You can also adjust how much weight the feeder will take before openings for seed close. 5 House Finches will close it.
I've watched squirrels at the local Nature Center trying to get into the other type of squirrel proof. The one that looks like a normal feeder with a bar for the birds to perch on. The center has it on a plain pole away from the building. If the squirrel tries to jump to it, he just slides off or closes it by hanging on the bar. They've had it for years and it must work.
I have the feeders on long poles attached to the porch railing. Everything is out of the damn deers' reach. I've got the heated birdbath up where the deer can't get to it. Bambi can get lost.