I have so much love for Gastornis aka Diatryma. Not only was it scratching 7 feet tall, not only was it flightless, not only was it likely a vegetarian…now they have found a fossil bone confirming its existence on Ellesmere Island! That means that adding to the entire surreal existence of this giant lumbering bird was the fact that it ambled around in swamps and wet forests in the DARK for 6 months each year! Their diets changed seasonally too, eating different things in the dark times of the year. Ellemere in the Eocene was at about 75 degrees latitude, now it is at 80 degrees.
On Ellesmere paleontologists have found fish, turtles, crocodilians, many clades of mammals ranging from primates to brontotheres, and birds5
Here is the formal article: http://www.nature.com/articles/srep20912