Items, NPCs, quests, objects and spells of patch 1.12.1, read live from the realm itself.

Patch of Bat Hair

NPC	Level	Zone	Chance
Vampiric Duskbat	8 - 9	Tirisfal Glades	18.3%
Ressan the Needler Rare	11	Tirisfal Glades	14.4%
Greater Duskbat	6 - 7	Tirisfal Glades	10.0%