Skree Wing

What drops it

 * Skree Griffin
 * Skree Singer
 * Skree Tracker
 * Skree Raider

Farming
There are three areas that can easily be farmed for Skree Wings.
 * Wilderness of Bahdza, before completing Destroy the Harpies.
 * Forum Highlands with the quest Desperate Measures active (at least 75 Skree will spawn).
 * Resplendent Makuun.