I can't stop updating this - help!
This thing now has separate stls and 3mf files to make a feeder for a wine bottle and also for a 2 litre pop bottle. They are clearly labled and very much smaller sized files than my earlier attempts.

When you click Download all, the 3mf files are towards the bottom of the list, and they are for the feeders. the stl files are for the accessories.

I don't think thingiverse displays 3mf format, which is what I have used for both feeders, but if you load one into Prusa slicer, it carries with it the modifier and its settings, and also the support settings, which is very useful. Amf does a similar thing, but the new version of Prusa slicer has lost the ability to export them (or I can't find how to do it!)

I've added a funnel which fits the pop bottle to help with filling.

I have discovered that an oval perch allows a wider variety of birds to feed.

The new feeders don't have a hole for the string to pass underneath, but instead there's an offset hook for the string to hold on to. That makes it more stable when filling it. The underside of the hooks need support, and that's why they are offset to avoid messing up the surface of the perch.

The "bottoms" support the wine/pop bottles and stop them from falling over, Recently I have taken to using a glue gun to stick them to the bottles. This removes the need to pass the string down to the hooks on the feeder below, although you may prefer to do so for a belt and braces approach.

This is a remix from 19/01/2022.

The info below was true, but the new one also flooded.
This remix needs to be printed in Prusa Slicer, as Cura can't make sense of it, sadly.
The base is now thicker and slopes upwards towards the seed dispenser to give an 8mm head to it (why didn't I think of that earlier??)

The modifier now imposes 45% Octogram Spiral on the base that needs to be free-draining.

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Thing 4441076 was for a wine bottle. This is modified for a 2 litre pop bottle.Although the original was very elegant and effective, when it rained, it flooded and the seed got stuck in the bottle.
So I redesigned it using Blender and Prusa slicer. I was able to put a modifier in the base of the feeder that removed the outer perimeters, and upped the % of 3d honeycomb infill. As a result, if will freely drain the full flow of my cold tap.
This remix has a larger version of the top, with the standard pentagon built in to match the pentagonal indents found on pop bottle bases, and the device can be hung now in the same way as the wine bottle version.
I hope you like it.
The .AMF and the 3mf files load happily into prusa slicer with all the present positions and settings.
When I tried loading it into Cura, all the parts sit on top of each other, and I don't know how to correct it or make it print. So some advice about this would be helpful. My inclination is to recommend using Prusa Slicer for this thing, as this file loads simply and effectively, without modifications.

Do let me know if this loads and prints well for you.