Modified primarily for multi-extrusion printers, but since I have quite significantly reworked the original model I decided to include single extrusion model too.
Other modifications (apart from preparation for color printing):
Remeshed/smoothed whole model.
Beak is slightly smaller and angled, so it is printable without support.
Wings are now more print-friendly, but supports are most likely still needed.
Left wing repaired (some slicers had problems with it).
Remixed from the model by me2space (thank you for nice penguin model!):