Black Vultures usually fly much higher than Turkey Vultures. Why?
The difference is their strategy for finding food. Turkey Vultures find dead animals by sense of smell, so they fly low. Black Vultures find dead animals by watching Turkey Vultures until they find an animal. Then the Black Vultures swoop in and take the carcass away from the Turkey Vultures. Flying high lets them watch several Turkey Vultures at the same time, increasing their chance to steal a meal.