(Squirrel) Resistance is Futile
So, the squirrel-proof birdfeeder comprises two hemispheres, hung via a string, with the sphere being held open by a spring. The idea is that when the Evil Mr. Squirrel decides to plunder the birdseed, he’ll have to put his weight on the upper hemisphere, thereby compressing the spring, thereby closing the gap and leaving him bereft of plunder opportunity. Birds, on the other hand, can alight directly on the rim of the lower hemisphere or enter inside. Here’s a picture of proper operation:
Alas, Evil Mr. Squirrel has two attacks on this system. The first is to climb onto the string, and swing violently back and forth until the seed falls from the feeder, then he harvests from below.
The second attack is to climb down the string, and jump repeatedly until he manages to catch the edge of the lower hemisphere, and somehow vault himself up. His Evil agility scarcely believable…