Alma Mater was originally intended to be gilded, but never was. The bronze eventually oxidized and the statue was instead coated and sealed.
Rumor has it that back-up Alma Maters are kept at the ready should need arise.
An owl is hidden in the folds of Alma Mater's robes. According to legend, the first student of each College class to find the owl would graduate Valedictorian and marry a Barnard woman (back when Columbia College was still all-male.)
Columbia's Alma Mater has a sister at the University of Havana. The Cuban Alma Mater was created in 1919 by Mario Korbel and inspired by Columbia's Alma Mater, while Korbel was residing in New York City. More recently, it served as somewhat uncanny validation for Bill O'Reilly's claim that Columbia is the "University of Havana North".
Alma Mater was bombed in the spring of 1970. The New York Times of May 15, 1970 reports that "a bomb partially damaged the statue of Alma Mater at Columbia University" and "tore a hole in the side of the statue."
In fall of 1984, Alma Mater's crown-topped scepter was stolen. Weeks later it was left with an anonymous note at the doorstep of David Drinkwater, Cornell's dean of students. It's unclear whether this heinous crime was perpetuated by Cornell students, or someone trying to frame Cornell. Nevertheless, shortly after the scepter's return, the statue of Ezra Cornell found itself doused in light blue paint. 
- Nearing Her 100th Birthday, Alma Mater Receives a Much Needed Makeover (January 2003)
- Columbia University Campus Photographs