Here is the excerpt from my game notes on the school's nickname

SAGES, WHAT’S SAGE?
People who are not from the area often ask, what’s a Sage. The nickname dates from the 1920’s when the then editor of the Champaign Gazette, predecessor of today’s Champaign News-Gazette, was standardizing school nicknames for the increasing popular and numerous high school athletic programs in his area. Some teams already had a mascot, but Monticello did not. His invention was to call Monticello Township
High School the “Sages” recognizing that Thomas Jefferson’s home for which the community was named was “Monticello” and Jefferson was called “The Sage of Monticello” thus the unique nickname “Sages”.

Again here is what is in my notes. I know that it goes back to at least 1962 when I started high school and probably back to before WWII as it is used in some of our yearbooks as they came out of the very simple version of the heart of the depression.

SAGES LOGO AND MASCOT
The current logo was adopted some fifteen to twenty years ago to reflect a more “combative”
image for the sports teams. Currently there is an increasing popular version that moves the
“attacking” aspect to a high level. The previous image was more reflective of the “Sage of Monticello”
tradition and featured an owl with a mortarboard. The mascot currently in use is in this
previous incarnation as the costume is a human sized owl. This costume is featured at MHS pep
rallies and some select home contests.