“How can you tell a bagpiper with perfect pitch?” (riddle)

A riddle about bagpipes is:
 
Q. How can you tell a bagpiper with perfect pitch?
A. He can throw a set into the middle of a pond and not hit any of the ducks.
 
The joke was posted on the newsgroup rec.music.makers.bagpipe on May 19, 1997.
       
 
Google Groups: rec.music.makers.bagpipe
Bagpipe Jokes
Scott L. McCluney
5/19/97
(...)
Q. How can you tell a bagpiper with perfect pitch?
A. He can throw a set into the middle of a pond and not hit any of the ducks.
 
30 June 2003, Battle Creek (MI) Enquirer, “Kid Scoop,” pg. 5B, col. 2:
Q: How can you tell when a bagpiper has perfect pitch?
ANSWER: When he throws his bagpipes into a pond without hitting any ducks.
   
Twitter
Doug Miller
@diggity
Replying to @amyguth
@amyguth what do you call a bagpiper with perfect pitch. One that can throw his pipes in the pond without hitting a duck.
4:17 PM - 12 May 2009
 
Google Books
The Biggest Joke Book Ever
By Jack Jacoby
Victoria, BC: Trafford Publishing
2012
Pg. 96:
How can you tell a bagpiper with perfect pitch? He can throw a set into the middle of a pond and not hit any of the ducks.
 
Google Books
Sensible Nonsense.. Frank’s Comic Pack:
Humour Pack Series
By Frank Paul
BookBaby
2014
Pg. ?:
Q. How can you tell a bagpiper with perfect pitch? A. He can throw a set into the middle of a pond and not hit any of the ducks.
 
Twitter
lorraine Jo King
@LahLahBean
#wednesdaywit
How can you tell a bagpiper with perfect pitch?
He can throw a set into the middle of a pond and not hit any of the ducks.
12:55 AM - 24 Oct 2018