Feeder for small birds

I previously designed and shared some bird feeders ([here](https://www.thingiverse.com/thing:4657703) and [here](https://www.thingiverse.com/thing:4787565)). I'm quite happy with them. But they tend to be used by large birds and small species struggle to get their share.

I hope this version will solve this issue. I designed it so the food (mainly seeds) cannot be accessible if the bird cannot fit its head inside the hole. And the distance between the stand and the hole is voluntarily short to prevent larger birds to easily get their way.

Only three parts :
* the main body is mainly a cylinder with a hole and a slope that brings the seeds close to the hole; it also features extensions on the sides, to hang the feeder to a horizontal branch or attach it to the trunk of a tree or a pole. There are two versions available: one with a bare hole and one with a little protruding ring around the hole, that acts as an additional visor.Note that this version requires more supports. I desig