The Phoenix was a magnificent, reddish-black firebird that was larger than an eagle, with a saffron chest, its head crested with scarlet, and its tail purple.
It was also seen in the True Narnia, when the Shadow Lands had ended, in the exact same location.
In the extended film version of The Lion, the Witch and the Wardrobe, a Phoenix was added to the Battle of Beruna scene.
During the battle, the Phoenix was used to create a wall of fire; it was signaled by the launching of an arrow, which exploded. Jadis's black-bearded Dwarf archers tried to shoot the bird down, but it dodged their arrows.
The Phoenix was successful in creating the wall of fire, though it did not hold off the White Witch's Army for long, as Jadis used her magic to clear the fire from her path.
In the film, the Phoenix appears to have a forked tail, and can set itself on fire at will.