The idea is not mine, but I must share.
This windmill repels birds well, and if it is mounted on a metal rod, then a bear and moles.
From the material you need a plastic bottle and that's it.
You will also need:
Marker
Scissors
Awl
Stationery knife.
To begin with, we cut the bottom from the bottle, it is not necessary to grow thin with distance, a small indentation goes along the edge.
On the cut bottom we mark with a marker.
In half, the protruding part.
Then along the edge of the concave part. I tinted it a little to make it clearer.
Then cut out the filled part.
Mark and cut (all in one direction, either clockwise or counter).
Then with a heated awl in the center we make a hole.
The diameter is slightly larger than the screw you have.
We also make a hole in the bottle cap. It is no longer necessary to heat the awl, since the self-tapping screw should be screwed into the lid.
Putting our propeller together. Between the self-tapping screw and the lid, I inserted home-made washers for better rotation.
We wind the fan on the rest of the bottle.
And do the awl two holes closer to the neck (this increases the windage of the windmill)
We bait the nail and nail to the prepared pole.
Now we go to our favorite beds and install a windmill-repeller.