Moa poo shows birds liked to nibble herbs

A study of fossilised moa poo has shown the giant birds had a surprising appetite for tiny herbs.

The findings, from preserved droppings that lay in caves and rock shelters for thousands of years, have overturned notions that moa snacked only on trees and bushes.

"It shows they were grazers as well," Otago University graduate Jamie Wood said. "Some of these herbs were just two or three centimetres high, but you have these giant birds eating them."

Another surprising discovery was that a native herb, ceratocephala pungens, that is now under threat, was once common.

"We found its seeds all over the place ... it's made us wonder if maybe the plant becoming endangered has something to do with the birds that were spreading its seeds becoming extinct."

Dr Wood, who starts work next week for Landcare Research, is studying moa droppings with Alan Cooper, director of the Australian Centre for Ancient DNA.

They examined leaf fragments, plant seeds and dna from more than 1500 faecal fossils known as coprolites.

The coprolites were mainly from species of the extinct giant moa, which grew to three metres high and weighed 250 kilograms. Some of the faeces were up to 15 centimetres long.

Most of the samples were found as Dr Wood dug at sites in the lower South Island for a doctorate on pre-settlement flora and fauna in Central Otago.

The droppings survived because moa sheltered in caves and rock shelters, leaving faeces that could last thousands of years if they dried out.

Last year the project won $768,000 funding over three years from the Marsden Fund. The initial results were already showing the value of the research, Dr Wood said.

Professor Cooper said similar work should be possible with the faecal matter of Australian birds, but evidence was so far lacking. "A key question for us is, `where has all the Australian poo gone?"'

- © Fairfax NZ News