Minor quibble -- 30D. The bird is obvious, as is "twice", but "rising vertically"? Seems extraneous & misleading.
Thought the transplants would be circular, but there's a disconnect.
Am left with 19A/3D which receives from 29A to replace the "core", the core of which is already there. No idea about the "old paper".
This means 7A doesn't have a donor.
Have I messed up somewhere? All the grid is filled & works otherwise.