Re: An Owl? Help Out this Librarian with a Stumper!
I can't think of a Heinlein work that even comes close to that story; it sounds like something for a much younger audience than anything Heinlein ever wrote for. (His well-regarded "juvenile" novels are for what we now call the YA market; he wrote no stories for younger kids.)
The only association between Heinlein and owls that I know of is a personal anecdote about him being given a stuffed owl, which resulted in the wry family phrase "about as useful as a stuffed owl."
I'm afraid I can't even guess at a possible author for such a story. Maybe someone else has a clue?
I will throw the query out on another resource and see if anyone there can guess.