September 20, 1944
From the March 1997 issue of Local 839's The Pegboard:
1985 Golden Award winner JERRY HATHCOCK died on March 8, 1997 at the age of eighty-four. From 1934 until his retirement in 1977, he worked as an animator, director and producer at Iwerks, Disney, Harman, UPA, Hanna-Barbera, Filmfair and Quartet.
Hathcock was a charter member of Local 839 -- one of the signers of the original petition that led to the founding of Local 839 in 1952. With his passing, only four of the original twenty-one charter members remain.
A partial filmography for Jerry Hathcock can be found at IMDB, while a list of 1301 cartoons he worked on is the result of a search on The Big Cartoon Database.
I'm not sure if this drawing means that birthday greetings are in order for son Bob or not.