Emory Environmental Science Professor Anthony Martin's observation of a behavioral pattern in coastal birds has led him to discover the oldest bird fossil in Australia and one of the oldest in the southern hemisphere.
Martin said he has conducted periodic research in Melbourne, Australia since 2006. In 2011, he made what he calls a "diagnosis" of the 105-million-year-old tracks in the storage basement of Melbourne's Museum Victoria.
In his book Life Traces of the Georgia Coast, he described the peace-sign-like marking made in sand by an egret, heron or shorebird skidding to a halt from flight.
He later identified this same "peace sign" in a museum as what others previously believed to be a dinosaur footprint.
Martin's research partners included award-winning paleontologist and Director of Melbourne's Monash University Science Center Patricia Vickers-Rich, her husband and Senior Curator of the Museum Victoria Thomas Rich and award-winning Monash University Geosciences Professor Mike Hall.
According to Martin, paleontologists and Museum Victoria volunteers Sean Wright and Alan Tait discovered the piece of sandstone bearing these footprints in Dinosaur Cove, a Victoria, Australia fossil site in 2010. It was Martin, however, who revealed their true significance.
Because the tracks date back to the Cretaceous Period, a time when Australia and Antarctica were still connected, the bird that produced them 105 million years ago lived in a polar environment rather than a sandy one, Martin said.
"To have a track that shows a bird flying in a coastal, polar environment makes us wonder: did they migrate?" Martin said. "That's the big question, but it's going to take a lot more research to find the answer."
He said he originally thought the prints were those of a dinosaur before realizing their similarities to those of present-day birds he had been studying on the Georgia coast.
"There's a point in geological history where bird and dinosaur tracks look alike – about 150 million years ago," Martin said. He added that his earlier observations of the tracks of seabirds more than 10,000 miles from those found in Melbourne forced him to reinterpret the imprints in the sandstone.
"I noticed the similarity while my book was still in progress, and there's even a part where I talk about bird landings," he said.
An entry in his website blog pairs the image of the Cretaceous Period tracks with one of great egret footprints in the sand of Jekyll Island, Ga.
His next book, Dinosaurs Without Bones, will be published in March. It covers his specialty, trace fossils: teeth marks, footprints, scratches and even feces of animals from Earth's distant past.
"If you took away bones, how would we know about dinosaurs?" he said. "That's the question this book answers."
Before publishing Life Traces of the Georgia Coast, he spent 12 years conducting research in the field and four years compiling observations. But the observations were not his alone.
"A lot of Emory students are featured in the book," Martin said. "They'll be thrilled to see these prints."
– By Lydia O'Neal
