Fossil find reveals ancient birds hatched fully fledged

PREHISTORIC birds living at the time of the dinosaurs hatched fully fledged from the egg, unlike their modern descendants, scientists revealed yesterday.

Most modern birds are born naked and helpless, while others are covered with down and develop proper feathers as they mature.

The evidence emerged from what is thought to be the oldest fossil of an unborn bird ever discovered.

About 121 million years ago the egg containing the embryo bird became buried in sediment at the bottom of a lake.

Scientists found the fossilised egg - smaller than most chicken eggs - in a lacustrine shale deposit in Liaoning province, north-east China.

Inside they discovered a hunched-up embryo at a late stage of development. But the most interesting thing about the unborn bird was that it had a large skull, feathers, and a hardened skeleton.

These are all signs that the hatchling bird would have been virtually fully formed and able to move and feed independently.

Scientists believe this “precocial” trait may have been inherited from the dinosaurs, which are believed to have given rise to birds.

Zhonghe Zhou and Fucheng Zhang, from the Chinese Academy of Sciences in Beijing, who reported the find today in the journal Nature, wrote: “Because these are close relatives to birds, the precociality of birds might represent a feature derived from their dinosaurian ancestor.”

The unidentified bird had toothed jaws and long curved nails, indicating a life in the trees.