The Terror Birds of South America; Dinosaurs and Other Monsters; Special Editions; by Larry G. Marshall; 8 Page(s)
It is a summer day on the pampas of central Argentina some five million years ago. A herd of small, horselike mammals are grazing peacefully in the warm sun. None of the animals is aware of the tall, vigilant creature standing 50 meters away in the high grass. Most of the watcher's trim, feathered body is concealed by the vegetation. Its eyes, set on the sides of a disproportionately large head perched on a long and powerful neck, are fixed on the herd. The head moves from side to side in short, rapid jerks, permitting a fix on the prey without the aid of stereoscopic vision.
Soon the head drops to the level of the grass, and the creature moves forward a few meters, then raises its head again to renew the surveillance. At a distance of 30 meters, the animal is almost ready to attack. In preparation, it lowers its head to a large rock close to its feet, rubbing its deep beak there to sharpen the bladelike edges.