Here is the full list of all 12 Copoka achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Collect all feathers, listen in on all major conversations and finish the story
Finish chapter 4
Finish chapter 3
Finish chapter 2
Listen in on all major conversations
Return to nest
Find the smuggling cave
Finish chapter 1
Attract attention from a walking citizen
Collect all feathers
Fly high
Add a trinket to your nest