I don't think there's any sure method. I've linked to one page which mentions most of what I've seen suggested. Some people have also suggested putting Cayenne Capsican Pepper and similar substances in the seed.

I had a similar problem with squirrels knocking the feeder to the ground each day. It was at the point I was about to stop filling the feeder. I switched to safflower seed and tweaked the position of the bird feeder. The squirrels still eat the seed, but are not as determined to get it. At the moment I have sunflower seed in until I receive the next safflower seed order through the mail. I haven't had problems again yet.

I've never put special food out for squirrels, but I usually see corn mentioned as a food they're very fond of. I don't know, but maybe they'd prefer corn to the sunflower seed.

If you search for "squirrel" on this forum you'll find some threads. I didn't go through them thoroughly, so I'm not sure whether or not you'll learn more from them.

By the way, now that they don't always knock down the feeder, I actually enjoy the squirrels here most of the time.

Good luck.

Here is a link that might be useful: From an Audubon site

There IS a way to install your feeders that is 100% squirrel proof. You need to mount the feeders on a pole, and use a squirrel baffle on the pole. The pole should be located not less than 6 feet from shrubbery, tree limbs, etc. that the squirrel can jump from to the feeders.

My 3 feeders are mounted on 2 poles, and both poles have squirrel/raccoon baffles (baffles purchased at Wild Birds Unlimited, but you can make your own). This setup has prevented squirrels, raccoons, and chipmunks from getting to my feeders.

Here's a pic of my feeding station to give you an idea. The baffles are those long black things on the poles. The baffles hang loosely on a piece of hardware that fits around the pole. Note that I actually had to relocate some shrubbery that was in this border, and move the shepherd's pole on the left farther away from the feeders, because the squirrels were jumping from them onto the feeders!

{{gwi:1349770}}

I have had no problem for several years. The smart squirrels seem to have died off. My feeder closes with a squirrels weight and the copper pipe pole is hard to climb. They stay on the ground and eat the spilled seed. One einstein climbed up and put one paw on another part of the feeder to take some of his weight off and the feeder stayed open. Haven't seen any doing that for several years.