In the process of researching my family's history, I found this clipping from "The Booster" of January 5, 1969, which I assume was the alumni newspaper at that time.  In case you are unable to read the text, it says:

 When Audubon School, 3500 N. Hoyne, recently celebrated its 75th birthday, former graduates from all over the city attended. In photo below, cutting a huge birthday cake are graduates from left:  Catherine Lassen, Melrose Park, class of 1903; Lillian Engelhardt, 3506 N. Hamilton, class of 1906; Walter Schaid, 2213 Winnemac, class of 1908; Louise York, 2045 School, class of 1908; Clara Gast, 4549 N. Leavitt, class of 1910.

My grandmother was Clara Gast, who is on he right of the photo.

 I'm sorry that the other items on the page were cut off.  Obviously my grandma only wanted to keep this photo!

In later years, all three of her children also attended Audubon School.  When I was a child (1950's), my father (her son) used to take me to the school's playground to play from time to time.