The Mage and the Magpie by Austin J. Bailey

Synopsis:

Brinley has spent most of her life lost in her own imagination, teaching bullfrogs to do gymnastics and pretending to be invisible. Now, when a magic bell from another world summons her across time and space on a journey to find her mother, she will discover real friendship, face true evil, and overcome her greatest fears in order to save the ones she loves. 

When Brinley arrives in Aberdeen, she finds that all is not well. The Magemother, is missing, and Hugo, a reluctant prince, is on a quest to find her. Together, they team up with an eccentric young birdkeeper and set off on a journey to solve the mystery of the missing Magemother. Just maybe, Brinley will find the answers to her own strange past along the way.