How the Blue Eagle became Ateneo's symbolSeptember 04, 2017
Ateneo de Manila University had adopted the Blue Eagle as a symbol, and had a live eagle accompany the basketball team by the late 1930s.
According to the school's official website:
It was a reference to the “high-flying” basketball team which would “sweep the fields away;” the dominating force in NCAA. Furthermore, there was some mythological—even political—significance to the eagle as a symbol of power. (From admu.edu)