The Diet of Gastornis
Popular TV vs. Peer-Reviewed Literature
My introduction to the large flightless bird known as Gastornis occurs in the 2001 BBC documentary Walking with Beasts, a 6-part miniseries that looks at "snapshots" of life, and especially mammal life, during the Cenozoic era (the geological era that begins following the extinction of the dinosaurs). The first episode takes place in the warmer years of the early Eocene epoch, some 49 million years ago.
Walking with Beasts characterised Gastornis as a predator, not unlike the "terror birds" that would later dominate South America. Walking with Beasts represented this belief by featuring a Gastornis chasing several mammals belonging to a progenitor species of modern horses. Video of one of the chase sequences (this one ending in success for Gastornis) below the fold: