Here is a quick illustration I made of Gastornis using a fossil skeleton as reference. Gastornis was a large flightless bird from the Paleogene period, standing almost as tall as a man and eating plant matter to sustain it's massive body. Being a masochist, I creating this in GIMP using a mouse (I certainly need a drawing tablet soon lol). I decided to change things up with this depiction by putting Gastornis in a meadow instead of the usual woodland-type ecosystem. While grasslands were nowhere near as common back then as they were in the Neogene period or the modern day, they most certainly would have existed in some capacity or another. I hope you enjoy :)