scientists discovered how to extract DNA from ancient egg shells.

The giant elephant bird of Madagascar could be resurrected after scientists discovered how to extract DNA from ancient egg shells. 

Genetic material from the bird along with extinct emus of Australia and moas of New Zealand have been collected by a new technique. 

In one case the DNA dated back more than 19,000 years.

Now scientists have discovered that egg shells are as good if not a better source than bone and hair. 

The flightless elephant bird – related to ostriches and emus – is the largest bird ever to have lived. It had massive legs, taloned claws and a long, powerful neck.

Its body was covered in bristling, hairlike feathers, like those of the emu, and its beak resembled a broad-headed spear.

It evolved at a time when birds ruled the earth and probably existed on Madagascar for 60 million years until dying out in the 17th century. In spite of its fearsome appearance it was a plant eater.

Eggs had a circumference of more than 3 ft and a length up to 13 in. Its volume is about 160 times greater than a chicken egg.

Ms Oskam and colleagues said: "Ancient DNA was successfully characterised from eggshell obtained from New Zealand, Madagascar and Australia. Our data demonstrate excellent preservation."

Bird eggshell is resilient and acts as a barrier to oxygen and water – the key causes of DNA damage. Modern shells also have antimicrobial chemicals and it also possible these remain active in fossil shells.