With Fall rolling back in, thought a Woodland/Owl theme party would be fun! Don't forget older, but still fresh!, Frosting for a woodland/owl party here (link)
How fun is this night sky backdrop?! Super clever! Some branches let you perch a few owls to set the scene.... Source
If you don't want to do a night sky... a fresh, light forest feel with lots of greenery, wood and other natural elements. Source

For treats, you can do anything that mimics the forest... these mushroom treats would be perfect! Perhaps slices of cheesecake topped with a cookie? Source
And I'll leave you the most clever use of royal icing... owl faces!!! Source and tutorial