Mistmantle Chronicles Book Four, The Urchin and the Raven War (The Mistmantle Chronicles)

After his last adventures, Urchin of the Riding Stars has taken his place as a trusted member of the Circle in King Crispin's court. Life on the island is back to normal, with little Princess Catkin growing up and testing everyone’s patience in the process.
But daily life is disrupted when Lord Arcneck and other inhabitants of Swan Isle come to Mistmantle asking for help. Their home has been taken over by bloodthirsty ravens that are attacking them and ravaging everything in sight.
The brave animals of Mistmantle rush to the aid of their friends, but in doing so, incur the wrath of the invaders upon themselves. The vengeful ravens are powerful and won’t stop until they hunt down and destroy every creature on the island. Only by using all of their courage and cunning will Urchin and his friends stand a chance to preserve life as they know it on their beloved home.