More ideas from Thodoris
I like the idea behind this and I could see it working with something other than birds.

Could also do as part of a gallery wall, or in a grouping with other similar frames (either with all birds or other things like trees, butterflies etc.) I might prefer to have the birds flying out of the frame instead of into it.

tree of knowledge

Line: The book shelf in the room shows the use of line because the book shelf shelves are built against the wall forming a miniature tree. Our eyes are drawn to look at the book shelf tree from bottom to top and outward to the tree/bookshelf branches.