This is how I would imagine the adult version of Kludd (from the Legend of the Guardians books) would look before he became the leader of the Pure Ones. In the movie, if you look closely, his parents are a lot bigger than both he and Soren, so I think they were still owlets at the time, but fully fledged.
Kludd is a VERY LARGE Barn Owl (Tyto Alba) as an adult.
I especially like the third book when the events start to pick up, and Soren finds out what happened to his brother, his OWN brother.
Oh and this was sketched digitally.