Where to Find All Hawkmoon Feathers
It's right at the exit of the Spider's Lair (the building where you accept the quest).
It's in the EDZ. In the Sludge (already collected it but it's where I stand).
It's in the cosmodrome on the building you spawn in (where I stand).
In the Dreaming City at the left side of the entrance of that huge building in the area where you spawn (where I point to).
On the moon in Oryx Shrine (Fanatic Nightmare Hunt). It's in the boss room so run to the end. To get to Oryx shrine go over Archer's Line into the hive building (where I point to).