LONDON.- An extremely rare egg, measuring over 30 centimetres high will be offered at Sotheby’s auction in London on 30th April 2015, with an estimate of £30,000 – 50,000. Believed to be over 400 years old, the egg comes from the Elephant Bird - the largest bird ever to live on the planet.

Now extinct, the great elephant bird – a giant flightless bird indigenous to the island of Madagascar - measured over three metres tall, and weighed over half a ton.

The elephant bird became extinct at some point between the 13th and 17th centuries, so this perfectly intact example could be up to 800 years old.

The egg will go on public exhibition at Sotheby’s galleries at 34 – 35 New Bond Street from Saturday 25 April until Wednesday 29 April, ahead of its sale as part of the Travel, Atlases, Maps and Natural History auction on Thursday.

The extinction of the elephant bird is widely believed to be the result of hunting. Archaeological studies have found remains of eggshells among the remains of human fires, suggesting that the large eggs regularly provided meals for entire families.

Due to their colossal size and extreme rarity, their eggs became sought-after rarities and curiosities in the late 19th-century – with the interest in them not having diminished to this day. Indeed, Sir David Attenborough, who owns another similar example, counts it his treasured possessions, as shown on his BBC TV series ‘Zoo Quest to Madagascar’. This particular egg comes from the collection of the successful Swiss carriage-maker and businessman Otto Alfred Heimburger, an enthusiastic collector of natural artefacts and specimens.