For those who don't know about this art, this is Li'l Bird Li'l Bird Colorful Colors is a book mentioned in the Black Rock Shooter anime. The book is stated to be about "a bird that takes people to a world of different colors".
The basic description is that the bird traveled to many different worlds and absorbed colors into its wings, such as "the blue of tears", "the pink of sneezes", and the "orange of smiles". However, it still wished to travel to new worlds, and it eventually absorbed so many colors that its wings became dull.
Dedicated to Sakuracherry! you art always amaze me and inspired me! keep up the gorgeous work *bows* Y U SO AWESOME!