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