2 questions about squirrel proof bird feeders...?

What is the shape of squirrel proof bird feeders and why are they this shape?2 questions about squirrel proof bird feeders...?
There are many types of ';squirrel proof'; bird feeders, in a large variety of shapes. Many are designed to be hard for squirrels to reach. The best sort (IMO) are spring loaded, and if a squirrel (or even a really large bird) is on it, access to the food is cut off.





see http://www.birdwatchersdigest.com/site/b鈥?/a>





We have this type: http://www.amazon.com/Brome-1024-Squirre鈥?/a> and it works exactly as advertised. Squirrels can get on it, but don't get any food. They've given up and now only eat the food on the ground that the birds drop.2 questions about squirrel proof bird feeders...?
I don't think there is such a thing as squirrel proof bird feeders, they are just obstacle courses to be concurred for the lil fellows. Most of the supposed squirrel proof feeders have are hung by a rope and have a round top over them that the squirrels slip off of. They are round and smooth so that the squirrels can't get a hold of anything and slip off.
Squirrel Buster.


It is a tube feeder for sunflower seeds. It works, and Rocky ain't torn it up yet.





They also make cage things, and baffles. If you can rig it, use electric fence wire to hang your feeders.





Squirrel spinners work too. Practically all anti-squirrel things are vast improvments over doing nothing.