This is a 3.8 cm (approx. 1-½ inch) entrance hole that suits the original ring. I wanted it to be slightly larger to attract birds that prefer this size, since the birds that are attracted from the 3 cm hole are pretty rare around here (I live in a semi-urban environment) but on the other hand the 4,5cm hole could attract unwanted species like sparrows.
No supports needed, just like the original. I prefer ASA as print material to withstand outdoor conditions as ASA is UV resistant and far more suitable in outdoor conditions than PLA.
A big thanks to the original creator for designing such a lovely piece of art!
The author remixed this model.