From Rovio:
A mystery has been unravelling across the Angry Birds universe. Previously known as Dahlia, Shade tinkered with a ritual from Gale's Ancient Book, combining a large black pearl and a ghost orchid. The resulting magical explosion transformed her into a ghostly white and incorporeal bird with a taste for dramatic entrances. Embracing her new form, she adopted the moniker Shade and has joined the flock.
Players who have passed Saga Level 23 can unlock this new, powerful infiltrator by collecting Shade feathers through special in-game events and modes, or through an in-game purchase. While festivities end on May 7, Shade will be a permanent addition to the flock for players who unlock her during the event.
