"Those are not normal vultures." Alice's whisper was her pause right before changing songs. It was mostly for her to ask Walker what was going on since she had no idea what they were.
Most people knew what a vulture was, there might be a few species, but for everyone, they were signs that something dead might be nearby. For adventurers, they were signs that there could be a larger group of predators nearby.
The vulture species would follow the pack of monsters or the large predator and eat from the remains of their hunts. A perfectly balanced relationship that would actually help protect more people in the long run since they could avoid the dangers that came with that predator.
However, these vultures had ink black feathers and their beaks and talons were white. While Walker could only see one that had lost some of its body to become an undead, the dark mana around its body proved to be more of a boost to the other death vultures around.