Australia’s Oldest Bird Footprints Discovered Dating Back to 100 Million Years

Palaeontologists have discovered fossilized footprints of two thin toed birds embedded in a riverbank of Dinosaur Cover in Victoria, Australia. The discovery of the footprints dating back 100 million years makes this finding the oldest known bird tracks on the continent.

The fossilized footprints are most likely of prehistoric birds from the early Cretaceous period. The scientists are optimistic about their find as they believe these tracks will offer information about the ancient birds that existed during the Cretaceous period and also on the evolution of flight.  

Anthony Martin, palaeontologists at Emory University, Atlanta, is leading the find. "These tracks are evidence that we had sizeable, flying birds living alongside other kinds of dinosaurs on these polar, river floodplains, about 105 million years ago," Martin who specializes in trace fossils, said in a statement.

The scientists claim that the thin-toed tracks were made by two individual birds the size of a small heron or the great egret. They were successfully able to distinguish the tracks as avian by looking at the rear pointing toes. These pointed toes were different from a third of the fossil tracks discovered at the same time, which belonged to some non-avian theropod (beast footed).

 What grabbed the attention of the palaeontologists was a long drag mark produced by a rear toe leading to one of the bird's footprints. "I immediately knew what it was - a flight landing track - because I've seen many similar tracks made by egrets and herons on the sandy beaches of Georgia," Martin says.

The beautiful skid mark in the moist sand of the riverbank, they assume occurred, as the ancient bird was preparing itself for a gentle landing. It is very rare to find fossils of landing tracks.  Today's birds are in fact the modern day dinosaurs and they share several traits with the non avian dinosaurs that are completely wiped out.

"In some dinosaur lineages, the rear toe got longer instead of shorter an adaptation for perching on trees," Martin says. "Tracks and other trace fossils offer clues to how non-avian dinosaurs and birds evolved and started occupying different ecological niches."

The dinosaur cove is a treasure trove of non-avian dinosaur bones. But only small fragments of bird skeletons have been discovered in the Cretaceous rocks of Victoria. The firs dinosaur track was discovered in 2010. Since then only a few tracks have been discovered.

What remains a mystery for Martin is whether the bird that made the tracks lived at the site during the polar winter or migrated to that place during the spring and summer. He believes the  tracks were made following a polar winter after spring and summer flood waters subsided.

The findings were documented in the Journal Palaeontology.