Some of the largest bird eggs in history were surprisingly also some of the most fragile. That’s the conclusion from Leon Huynen from Brisbane University, who has been studying the eggs of an extinct group of flightless birds called moas. These giants roamed New Zealand until the 14th century when they were wiped out by humans. Today, all that remains are bones and eggs but some of the broken shells have preserved traces of the moas’ DNA. Earlier this year, Australian scientists sequenced the genes of moas for the first time. Now, Huynen has used the same techniques to work out how these birds cared for their young.

By sequencing DNA from 69 shell fragments, he worked out