The tabloid newspaper wars in New York have taken a strange turn. Yesterday, readers picked up Rupert Murdoch's New York Post and turned to Page 6 for the personalities items and the Rigby cartoon across the top. Readers of the competing New York Daily News, turning to its Page 6, found a Rigby cartoon across the top of that page. Now that's impossible. On closer examination, the Post's cartoon was signed Bay Rigby, who is the 21-year-old son of Paul Rigby, 60, who was a Murdoch cartoonist for 25 years, the past seven at the Post, and is now at the Daily News.

The elder Rigby "retired" from the Post with the knowledge there was a Daily News offer. Both he and his son, whose name is also Paul, deny there was any plan to get the younger Rigby hired away from the Boston Herald to the New York Post.

Rigby said it is strange, since he and his son live in the same house, to ask, "Who's going to use the drawing board now?" Bay Rigby, who got his start at 18 on the Adelaide News in Australia "where Pat Oliphant got his start," said he will soon find his own place to live, but is pleased that he and his father may be a historical first: the first father-and-son cartoonists to be competing against each other. As if New Yorkers don't have enough things to confuse them.