Alright posting this up as a question. Where the heck was I supposed to use this whistle at? I have been all over the Blackpits, talked with every dead magister ghost I can find and yet the whistle does nothing. Talking to the paladin just has him repeat "I haven't received your owl yet." so that isn't helpful and checking back to old dialogue shows I don't have it anymore. Guess I talked to too many people.
The answer will be greatly appreciated!