Bird fossils ‘key’ to map of Cradle of Humankind landscape

The Cradle of Humankind is like the global celebrity of palaeontology: from Homo naledi to Australopithecus sediba, our fascination with our ancestry (and controversies surrounding it) has taken us into caves far below the surface of the Earth.

The latest study, however, focuses on the delicate bones of birds and gives us rich clues about the landscape and lives that once formed part of the ecosystems there.

Scientist Marco Pavia, of the University of Turin in Italy and Wits University in Johannesburg, studied more than 800 remains from a bird assemblage at Kromdraai.

The study, he says, “revealed the presence of 25 bird taxa (biological classifications)” and “for some of the taxa, Kromdraai represents the oldest fossil record so far, if not the first ever”. 

The assemblage represents a sample of biodiversity in the bird kingdom and includes rock-dwelling birds, open-grassland birds, freshwater birds, ducks and waders, and forest birds.

“The presence of these taxa, and their percentages in terms of the number of bones and individuals, point to the presence of a cliff or important rocky outcrop very close to the fossil site, with the presence of a waterbody and a gallery forest,” explains Pavia.

He adds: “The grassland birds and their numbers confirm the presence of open grassland or savannah, which was already indicated by the analysis of large mammals.”

These results shed new light on the environment of the Cradle of Humankind during the Plio-Pleistocene era about five million years ago.

The Kromdraai (“crooked turn” in Afrikaans) location is a roofless dolomite site two kilometres from the famous Sterkfontein Cave and has been offering up pearls of palaeontological wisdom for almost eight decades.

In 1938, a local schoolboy, Gert Terblanche, found several hominin teeth on the site and these were brought to the attention of expert Robert Broom.

The teeth, it was discovered, fitted a skull that became the holotype of Paranthropus robustus, a hominid with very large cheekbones and a face shaped like a dish.

From then, Broom began excavating the site in an expedition that went on for a decade and yielded several hominin remains.

Then, in 1955, a new excavation revealed more hominin remains, as well as many animal remains. Then, in the 1980s, the site revealed itself as a rich deposit of bovid remains.