Red and gold male Phoenix Fawkes is an intensely magical creature, possessing a number of magical abilities, the precise extent of which are unknown, but which include: carrying immensely heavy loads; his tears have healing powers; encouraging song; can regenerate by bursting into flames; can disappear and reappear elsewhere at will. Two of his tail feathers from him were used to make wands. One for Lord Voldemort and one for Harry Potter. Tame phoenixes are very rare and he serves as proof of Albus Dumbledore's abilities and character. Fawkes is a herbivore.
Whenever Fawkes dies, whether it be by violence or old age, he bursts into flame and is promptly reborn out of the ashes as a baby phoenix. As an adult he's about swan-sized and quite beautiful, but his infant stage Fawkes has the appearance of a newborn chicken and in his geriatric stages he has dull, limp plumage.
After Albus Dumbledore's death in Half-Blood Prince, Fawkes is heard singing a lament for him. When the singing stops, Harry somehow knows that Fawkes has left Hogwarts forever. It is not known where Fawkes has gone, or if he may perhaps appear in the final book.