This needs a 5mm carbon rod and a plastic canister/little bucket.

Made it to fit a default nut bucket the nut shop is using.

Bottom goes under the bucket. The inside goes inside. Two screws go through to fix it to a plank or piece of wood. 

The carbon rod needs to be glued into the inside piece.

This setup is some iterations from the start. At first the squirrel manged to break the inside piece by pushing the rod too much.

I had a hollow lid that caught the squirrels ears with led them to panic and break stuff.

Closed the bottom of the lid but it was hard for them to push it up.

Now created a tube that can move so the lid can lift a bit but still slide along the tube.

This seems to be working out fine and still in one piece.

Print instructions: make sure to have support in the middle for the top tube. Tree supports for example. There are some build in break-away pieces to stabilize the tube during print. When printed by moving the tube they will break loose.

added v6. larger with less angle and a cap to let rain go over the joint. The other version sometimes could get the edge into the bowl and stick in angle open letting rain (and birds) in. print with minimal infill to keep it light. I recommend regular supports for the raised circle that goes over the edge of the bowl.