Squirrel-Proofing Your Bird Feeders:

This challenge brings out a primitive "man against animal" instinct in many of my friends which have tried everything from greasing the poles to electric shock to stop the them. Squirrels are very ingenious even understanding Newton's laws. Putting myself inside a squirrels brain I conjectured that they would think chewing the cord between two trees from which the feeder hung would destroy their path to the food, but they figured out that gravity would bring the food to them.

General Guidelines:

1. Squirrels can jump 4.5 ft vertically and 6-10 ft across from a tree. Some recommend spacing of 12 feet or more from any surface the squirrel can jump from, such as a tree, shrub, or house.
2. If pole mounted feeder with a baffle is the only sure fire solution, put a Wrap-Around Squirrel Baffle on the pole below the feeder at least 4 ft high. The baffle must be longer than the squirrel's reach (15 in for a grey squirl)
3. Don't believe the "Squirrel Proof" labels on feeders.
   Derek Lovitch of the Wild Bird Center in Yarmouth says the Squirrel BUster Plus (below) is the only one he's found to be 100% effective.
4. Placement is important.
   South side will be warmer in winter. Place within 8 ft of woods or shrubbery where birds can go for protection for predators like hawks.
5. Myth - Birds will become dependent on feeders which will interfere with migration, natural diets, etc.

Feeders hung from a tree:
String empty film canisters, empty plastic soda bottles, sections of hose, old vinyl records, spools of thread, or PVC pipe all along the wire. Use any objects that will cause squirrels to slip off the wire if they walk on it.
I tried this with plastic soda bottles, a coffee can with a frisbee glued on the end, and they learned how to balance on them. I fastened the line higher on the tree so it hung down in a V shape and the still got down it.

Mission Impossible Squirrel - YouTube
Twirl-A-Squirrel.