Sister Mary Bird Mystery?

In my Grade 10, a member of the staff was Sister Mary Bird. I was in one of her classes. However her name is absent from the list of nuns teaching at the school. Maureen Moloney compiled the list with information from the Sisters of St. Joseph, so obviously there was an oversite on someone's part. I can't remember what subject Sister Mary Bird taught. Any enlightenment would be welcome.

Pictured beside her in the yearbook is Tony White. Incidentally this comes from the yearbook that is the photo frontispiece for this blog.