Regarding squirrels as nemeses is intrinsic to most homeowners and/or bird-lovers. One of our first decorative efforts after closing on our house a few years ago was to hang bird feeders in the yard, and we started fending off squirrels before I made it back down the ladder.
There are all kinds of technologies, preventative measures, architectural approaches, diversionary tactics and weaponry developed in response to the "squirrel problem". One thing they have in common -- they're all profoundly ineffective.
Our most recent response to squirrel-frustration was to string a series of empty 1-liter soda bottles along a tightly-strung wire anchored between two maple trees. The strategy here was to frustrate the squirrels by making it impossible for them to get their footing along the path strewn with the bottles, which would rotate around the wire. We collected bottles for months, installing our fiendishly clever contraption this past weekend. Birds immediately flocked to the feeders -- chickadees, woodpeckers, blue jays, golden finches. We didn't see any squirrels attempt to reach the feeders but knew from bitter experience not to declare "Mission Accomplished!" too quickly.
A few mornings later I came downstairs and looked out the window toward the assembly, where I spied a gray squirrel preparing to step out onto the line. As soon as he'd placed three feet on a bottle and released his grip on the tree with his fourth, he started to spin around like a lumberjack with vertigo in the midst of a log-rolling competition. He (the squirrel) hurtled to the ground, looking panicked and disbelieving. Once he gathered his wits he perched on his hindquarters, peering up at the feeders and calculating if he could muster the vertical leap sufficient to reach them. Deciding that was not an option he scampered back up the tree, pausing two feet above the line's anchor. He then leapt into the air, sailing past eight of the bottles and landing atop the closest feeder. He grabbed onto it like a drowning sailor clutching at a life preserver dangling from a Coast Guard helicopter. Once he established his footing, the squirrel began methodically poking his face through the "squirrel-proof" wire cage surrounding the tube and gorged on the black oil sunflower seeds contained within, eating like a creature who was tired of awkward similes and just wanted to stuff his little rodent face.
Another strategy is to put out types of seeds the squirrels don't like, such as Nyjer (also known as thistle). I can attest that our feeder filled with Nyjer rarely sees a squirrel visiting it. Also, very few birds. The seed is supposed to attract vireos, sparrows, redpolls, siskins and juncos, among others. So far, we've yet to see any vireos, sparrows, redpolls, siskins or juncos at that particular feeder -- although we've seen squirrels resting on its base while gazing warily at the unpalatable offering in front of them, then looking around for a waiter to bring their correct order.
We have another type of feeder that is weight-sensitive; birds are light enough not to trigger it, but something as heavy as a squirrel or raccoon will pull down on a spring, causing the casing to drop far enough to cut off access to the feed windows. So, naturally -- the squirrels manage to burglarize that one by holding onto the hanger with their hind feet so they don't pull down on the spring and can then reach the food within while suspended upside down. I admire their display of core strength; maybe they should feature squirrels in those "Total Gym" commercials instead of Chuck Norris or Christie Brinkley, whose only time spent strapped to that contraption is during house calls by their plastic surgeon so they can't squirm when he injects them with more Botox.
The local feed and supply stores try to have it both ways, stocking allegedly squirrel-proof devices along with food marketed as appealing those very same little bastards. We figure we're already providing them with heavy hors d'oeuvres so no need to also serve a main course. Taking a step back -- you really do have to admire their ingenuity and perseverance. Putting their relentless effort in context: they are scavenging only for what they need to survive, driven by hunger and their animal nature.
Now, please excuse me while I raid the refrigerator since I think I saw a piece of fried chicken in there.