Wildsmith: The Hidden Sea by Liz Flanagan

From Union Square Kids:

Fans of the Unicorn Rescue Society and Wildlore series will flock to this cozy, fantasy quartet about a young girl who discovers she’s a wildsmith—someone who can communicate with magical animals.

On the heels of another successful rescue, Rowan finds herself far from home. She and Mouse, the Pegasus foal she is protecting, seek refuge on Thornback Island, hiding away from the relentless poachers who will do anything to capture the mystical creature.

Though she makes new friends and her days are filled with unexpected adventures on the island, Rowan worries...will she ever find her way home?