Speak to Vadicus Entiri at -2394, -668, -226 in the Sanctuary of Waning to begin this quest.
Even though this quest is marked as heroic the mobs required are only ^ difficulty and it can be soloed.
Kill 4 withertalon alphas, which can be found around the upper entrance tunnel to the Withertalon Breeding Caves at -2391,-591,-383 or inside the breeding cave.