Summary

Initially made for the Weather Vane ( https://www.thingiverse.com/thing:7069847 ), as a North indicator, but it evolved into a new thing. It's a standalone design
I also added a shell shape (looks like an armadillo) if the blocky shape doesn't suit you. And a door plate with a larger entrance. Maybe I'll do a rounder version later idk

The blocky birdhouse part needs a simple central support when laid flat on the bed, for the back wall of the bird house (not for the ring! flip it around).
The armadillo birdhouse part is best printed "tail up". and it doesn't really need supports. pro tip: don't paint it in ugly gold like I did

There's a short version of the thick blade, in case you don't intend to use it as a North indicator for the Weather Vane. For both of these I recommend using glue.

Took a picture of the real thing, and I agree with you: gold is not a nice color for it. Anyways...

Printable on a small 180mm bed.
Bird house size:
entrance: 3, 5 or 25 cm diameter depending on the door version
inner space: 9x9x9cm or 10+cm diameter sphere volume

Materials:
Filament: Being as it's going to be used outdoors, I'd use a proper filament. Like HT PLA
Bolts : short M4s, but you can get away with wood carpenter screws too. The same for mounting it on a wall.

My prints tend to warp 2-3mm in size sometimes. If yours do the same, I'd shrink the thick blade a little. It's too snug for comfort