http://www.newsweek.com/elephant-birds-biggest-avians-walk-earth-were-practically-blind-1193803

The African island of Madagascar was, until relatively recently, home to the largest birds that ever lived. Known as "elephant birds," somes species grew to heights of around 10 feet tall and could weigh up to 1,800 pounds.

The biology of these massive, flightless birds is mostly unknown, but scientists have long thought that they were primarily active in the daytime and had good eyesight like the vast majority of species in their animal group (ratites)— which includes ostriches, emus, rheas, and cassowaries.