As everyone else has mentioned, the only realistic place to get Dragorn Wing Bones is the two zones in Seeds of Destruction expansion. You can't farm this in Omens of War zones - the drop rate is too rare.
Most of the friendly dragorns in these two zones were changed to not leave a corpse, hence no loot, so that mostly leaves just a limited number of evil and neutral dragorns to kill, but their drop rate is good.
Old Bloodfields (SoD)
SE: 10 a dragorn muramite (6 static, 4 roaming) - 10 min respawn - 1 could be Taath, 1 could be Pherin the Traitor
SW: 3 a dragorn muramite (3 roaming) - 10 min respawn
far NW: 6 a dragorn courier (6 static) - 10 min respawn
far NW: Noble Mikuv the Rational (static) - 10 min respawn
far NW: Defender Guland (static) - 5 min respawn
Total: 21 mobs
City of Dranik (SoD)
3 a dragorn thug (1 static, 2 roaming) - 10 min respawn
- a dragorn patroller is PH for thug, but is on friendly faction, and has no loot