Here is the full list of all 15 Riddles of the Owls' Kingdom. Magic Wings achievements.
20 levels with 3 stars
"Garden in Bloom" world complete
Tutorial finished
Solved level in less, then 120 seconds
Hints used in 3 levels in a row
60 levels with 3 stars
Collect all owls in Merlin's office
40 levels with 3 stars
"Old Library" world complete
"Vaulted Caves" world complete
100 levels with 3 stars
"Crimson Field" world complete
Fully restored Merlin's office
All levels with 3 stars
All Trophies collected