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

Horn of Hatetalon

NPC	Level	Zone	Chance
Northspring Harpy	48 - 49	Feralas	100%
Northspring Roguefeather	48 - 49	Feralas	100%
Northspring Slayer	49 - 50	Feralas	100%
Northspring Windcaller	49 - 50	Feralas	100%