Moa mamas

Artist's impression of a Moa and egg by graphic artist Vivan Ward. Photo / Supplied

Scientists have found proof that the female moa was such a big bird, and her eggs' shells were so thin, that if she sat on the eggs, they would have broken.

Auckland University's Dr Craig Millar said the moa's fragile eggs, coupled with the size of the female birds, would have made incubation difficult.

"They can't do what other birds do and just put their full weight on their eggs."