An extremely well preserved and almost complete (90%) fossil of the South American Terror Bird (Llallawavis scagliai) discovered by Argentinean palaeontologists on a beach in Mar del Plata in 2010 has allowed them to conclude that the 10-foot-tall (3 meters) carnivorous bird had a deep chirp. This finding was made possible due to a detailed study of the long extinct predator’s hearing and anatomy which walked the South American continent 1.5 million years ago.

The fossil found on the cliffs of La Estafeta beach, a region close to Mar del Plata, a popular tourist destination, led to the discovery of a new species called Llallawavis scagliai. “llallawa”, In Quechua, the native language of the people inhabiting that region in the central Andes, means “magnificent” while “Avis” is the Latin word for “bird”. “Scagliai” is used in the name of the bird as a sign of honor for the famous Argentine naturalist Galileo Juan Scaglia.

“The mean hearing estimated for this terror bird was below the average for living birds,” said Dr. Federico “Dino” Degrange, lead author of the study who hails from Argentina. “This seems to indicate that Llallawavis may have had a narrow, low vocalization frequency range, presumably used for intraspecific acoustic communication or prey detection.” This is the first time that the structures which indicate hearing sensitivity have been reconstructed for any terror bird, and they may help explain the evolution, behavior, and ecology of this group of fossil birds.

Discovering such an old fossil in an almost complete state is extraordinary. More so in case of birds since their builds are light and they have hollow bones.

“It is quite rare in South America – almost impossible if you think thoroughly,” said Degrange. “There are few places where delicate bones, such as those of birds, remain as beautifully preserved as Llallawavis.”

While mentioning these findings in the Journal of Vertebrate Paleontology, the researchers said they expressed hope of being able to review the hypothesis about the decline and extinction of this fascinating group of birds after knowing more about their anatomy.