A Witnessing of the Hatching of a Caterbird from its Cocoon was a treatise that Xanth Filatine planned to make during The Last of the Sky Pirates. However, after his accident at the first flying lesson that left him crippled, he was unable to ever set out to write it. After he rejoined the Librarian Knights in Freeglader, he was able to fly again, so he may have written it at some point between Freeglader and the birth of his son, Rufus in 89 ᴇ.ʏ.