Turkey vultures locate carrion by their acute sense of smell. They do a great clean up service for our earth. But they lack the ability to screech because they have no syrinx. So, when they are stressed, their head pales from its “normal” redness. This nonverbal method is their way to convey warning to others.
The featherless head of the turkey vulture is a great design! Not have feathers means they don’t have to worry about bacteria, parasites, and disease as their head stays clean when they are eating carrion.
Turkey vultures have communal roosts. These serve several functions, one of which is for young birds to learn from the older, more experienced birds.
To learn more, check out All About Birds