Blood Vultures

The Blood Vulture is a large, predatory bird that lives high in the Mountains of Mourn. Although primarily scavengers, blood vultures have no qualms about attacking living creatures, swooping and slashing at their victims with their sharp claws and powerful beaks. Ogre Hunters capture and tame blood vultures, and use them to hunt down prey or attack their foes in battle.

Source

 * Warhammer Armies: Ogre Kingdoms (8th Edition) -- pg. 37