I read a book about twenty years ago with main characters of an owl and I think a cat. The animals are sentient and are ruled over by a great king who is a falcon or eagle. The owl and cat are caught up in events and end up in the company of the rightful. Some years earlier, the king had had to leave and left his trusted advisor as his regent. It's the common story here -- regent slowly falls in love with power and by the time the king returns the regent is willing to fight to keep the power he now considers his own. The owl and cat help the king keep his throne. I think that the eagle/falcon had some magic and could allow the cat to run at incredible speeds as long as he was inside or touching the king's shadow.

I read this book about twenty years. Forest animals are sentient in this book. The main characters are an owl and I believe a cat who are friend. These two are noticing some strange thigs going on around them and want answers. They are recruited by an eagle/falcon to help him. For some reason in the past, the eagle/falcon who is the rightful and powerful king of the forest had to go somewhere else. Th king left a trusted advisor to look after his people. Of course this regent grew to love his power and would not yield to the true king. While the cat was in the king's shadow, he could run as fast as the king was flying.
Thanks