This is v3 of my bird feeder which holds ~1 kilo of seed.
The first was 150mm tube sized and held +3 kilos of feed !!!

Features:

1. Prints on a 200x200x200 printer with less than a 3/4 Kilo of filament !!!
2. Sixteen M2 x 8mm screws for assembly.
3. FUNNEL to make filling easy - Print with top edge on the build plate.
4. TOP HAT fits on Hanger snugly - Print with bottom edge on build plate.
5. ROBUST HANGER - Recommend 100% infill on this piece for durability.
6. EXTENSION TUBE - Optional. Try it without and add more feed capacity later.
7. 8 FEEDER STATIONS - Add SUPPORT on the station window overheads. This takes a while to print because of the drain holes on the bottom.
8. PERCH - Print 2 with flat side on the build plate and screw holes up - with 100% infill and use BRIM to hold on the plate.

We have large, medium, and small birds able to feed easily.

The Perches are probably the most important design component beyond the variable size, easy assembly,  and robust nature of this design. After observing bird behaviour on several other commercial feeders I realized the angle of the perches was leading to difficulty feeding. These perches have a triangular shape with a center spar which allows for a myriad of perch angles. All day I see individual birds land and adjust to a  comfortable feeding angle.