Mr JA van Tilburg bequeathed his "prentenkabinet" of over 10 000 graphic works to the University of Pretoria.
Between the years 1921 and 1958, Kuperus drew and etched animals in the Amsterdam Zoo. In 1936 the birth of a young lapwing (kievit) was reported at the zoo in several newspapers. At least one of these newspapers mentioned an artist for the zoo drawing the young bird.
