Napoleon: As the extremely ambitious (although slightly delusional) leader of the group, Napoleon came up with the idea of taking classes at the college- in his case, Political Science classes. 'Taking classes' generally consists of peeking through class windows, listening in on the human students, and occasionally sneaking into the classes by hiding in the humans' backpacks. He doesn't care that his method of attending classes is unusual, since it means that 'tuition' is free! He hopes that by getting an education, he will one day find a way to overthrow the humans and eventually take over the world.
Emily: Curious and artistic by nature, Emily became fascinated one day when she saw the Fine Arts students through a window on the third floor. She began to observe them every class and, due to a lack of proper supplies, began to experiment with using her wings for a brush and various substances (for example, mud and ketchup) for paint. Walls of the college and other nearby buildings became her canvas. She named her technique "featherism" and it's already becoming popular among the pigeon art community.
Buster: Buster isn't really interested in school, despite the fact that he is smarter than some humans! He would much rather spend his time scouting for food or just hanging out on his favorite perches. When he believes no one is watching, however, Buster will occasionally 'attend' various classes as well, hoping that he'll eventually find something that interests him enough to pursue as a career.