Originally Posted by
GrouchoTheCat 
The new person or "Sponsee" if you will, is referred to in the big book as a Protege.
Noun 1.
protege - a person who receives support and protection from an influential patron who furthers the protege's career
recipient, receiver - a person who receives something
As far as I know, there is no mention of the word pigeon in the book.
What an insult.
Well Groucho, read Dr. Bob and The Good Old Timers and you'll discover that Dr. Bob coined the name "Pigeon" and used it in a loving and respectful manner in refering to his "babies" which is a term he also used.