Symbolism, Imagery, Allegory
When Wisty's carted off to jail, she's allowed to take one personal item. When her mother hands her an old drumstick, she can't help but feel a little disappointed:
A drumstick or an old book? How about a drum to go with that stick? Couldn't they give us a family heirloom or something vaguely personal to cheer us up? (6.14)
We feel you, Wisty. A drumstick is no kind of parting gift. Of course, as it turns out, the drumstick is a magic wand—something that readers will likely realize long before Wisty herself does. And this is part of the point: Wisty doesn't understand just how magical she is. It's only as the book ends that she seems to really be wrapping her mind around who she is and what she's capable of.
In one of the last chapters, the drumstick finally assumes its true form when Wisty is reunited with her parents: "Look into my eyes," her mother tells her. "All of the secrets are in there" (103.18). After Wisty does, her drumstick turns into a magic wand, making it clear that wisdom and knowledge have been transferred from mother to daughter.
Interestingly, Wisty's mom says the drumstick/wand symbolizes her future career in music. Given that there's no indication in the book that Wisty has any interest in music, this comes as a surprise. But hey—if that's her fate, a magic drumstick will certainly come in handy.