Map drawn by Hoochief
A map that marks the locations of the cages in the eastern forest and the Hoochief camp.
Details 
Category: Quest Item
Rarity: 3
Background Description
Out of hatred for humans, the Hoochiefs in the Dim Forest will use tree cages to imprison passers-by. They use the hides of other creatures in the forest to crudely imitate humans and draw maps to remind the locations of the tree cages.
Map on Animal Skin
Five markings shaped like cages, one of which seems to hold something special.
As for clues to unlocking the cages, maybe look for the extra markings...