Fossil reveals terror bird’s power

Beak strong enough for ancient South American predator to hatchet its prey

Terror birds, such as the newly identified Llallawavis scagliai (illustrated here), were South America’s top predators millions of years ago.

H. Santiago Druetta

With a swift hatchet of its beak, the terror bird Llallawavis scagliai could have whomped its prey, a new fossil find confirms.

Terror birds were one of South America’s top predators from about 50 million to roughly 1.8 million years ago. Researchers from Argentina have discovered a nearly complete skeleton of a new species of terror bird in a cliff face close to Chapadmalal. The researchers call the bird Llallawavis scagliai —Scaglia’s magnificent bird — in honor of naturalist Galileo Juan Scaglia, the grandfather of one of the researchers. They describe the fossil in the March Journal of Vertebrate Paleontology.

Included in the skeleton is a tiny bone that strengthened the connection between the bird’s beak and skull. It is the first time scientists have found this bone in a terror bird fossil, providing direct evidence that the birds’ beaks would have been sturdy enough to be used as a hatchet while hunting.

L. scagliai stood roughly 1.2 meters tall and weighed about 18 kilograms. It roamed South America around 3.5 million years ago. Its existence shows that more than one species of terror bird was bullying the continent’s smaller creatures at the time, the researchers report. The finding also suggests that mammals moving in from North America around 5 million years ago didn’t force terror birds to go extinct, as many researchers had thought. What caused the big birds to die off is still an open question, the scientists say.

A nearly complete skeleton of L. scagliai offers new details about how terror birds interacted with their environment millions of years ago. M. Taglioretti and F. Scaglia
A tiny bone connecting the beak and skull of L. scagliai provides evidence that terror birds used their beaks as hatchets when hunting. F. Degrange

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.