This is the bearded vulture. It lives in the mountains so it can look down on us all. It smashes bones for a living. It encourages its children to fight to the death. And... it dyes its feathers. Why? Because it looks awesome, that's why.
Bearded vultures were once nearly driven to extinction because people from Europe to Africa were certain that they would pick up, carry away, and eat human children. That's not true, but it's easy to see why people made the mistake. Bearded vultures are big — nearly 18 pounds. They have a vicious disposition. They lay two eggs, but only raise one chick. The larger and stronger chick drives its sibling out of the nest to die. They're territorial. Each needs a few hundred kilometers to call its own, and will fight any other vulture that comes close. They come with claws and beaks that look like something you would need a permit to carry around with you. They use both their claws and their beaks to eat bone.
When I say that they use their claws and beaks to eat bone, I don't mean, "every part of the animal, including the bone." I mean bone. The bearded vulture's diet is from 70-90% bone. This means they don't have to compete for food with other animals. The vulture looks for fresh kills, waits while the other animals strip flesh from the bone, and then swoops in. They can eat smaller bones whole. Larger bones they carry up into the sky and drop on rocks, then swoop down to eat the marrow and the fragments. Occasionally they'll supplement their diet with small, whole animals, but for the most part, they live on skeletons.
And then there's the matter of their plumage. Their feathers are black and white. That's right, white. Why are the feathers above pink? At first researchers thought the bird's diet sometimes allowed it to produce carotenoid pigments, but those aren't pigmented feathers — they're stained feathers. And, because the vulture eats bones and not flesh, it's not blood staining the feathers.
Bearded vultures are the only birds known to deliberately dye their feathers - and they know the colors they prefer. Though some vultures will stain their lighter feathers with brown dirt or yellow dirt, when a vulture has access to dirt with "iron oxide," it will deliberately rub the dirt into its feathers and preen for more than an hour. That's right, to look sufficiently blood-thirsty, this bird deliberately seeks out rust, and uses it to dye itself red, just because it looks cool.