This cartoon almost came out okay. It's really just making fun of the stars of Hollywood in 1938. It has Katherine Hepburn as Little Boy Peep, W. C. Fields as Humpty Dumpty, and even the Marx Brothers make an appearance. But then Eddie Cantor opens a scene by singing, "20 black birds baking a pie," and a number of unnamed African American jazz artists, crudely drawn, pop their heads out of the pie. One is Cab Calloway singing "Hi-de-ho." Feel free to skip forward to 5:00 to see the offending bit if you don't have enough patience to figure out all the old actors.
The "Black Birds" in Mother Goose Goes Hollywood (1938)