[NorthMountain]

I have a bird feeder with a spring loaded perch; anything too heavy gets on it and:

1) The perch drops, closing a door over the bird seed

2) The perch really drops; anything trying to perch on it (like, say, a squirrel) gets unceremoniously dumped about 6 feet to the ground.

It's too big for a squirrel to perch on the top and reach down to get the food. I saw one try, once. It was funny.

[Songcraft]

I think I have to try to find one something like that too.   That sounds like one that really works.