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Old poo holds answer to moa diet
Scientists from Landcare Research and the University of Adelaide plan to study the fossilised poo of moa to work out what the giant birds used to eat and what effect their snacking had on the ecosystem before humans and other mammals arrived in New Zealand.
Weighing up to 240 kilograms, the moa were the largest herbivores in New Zealand until their extinction about 600 years ago. It is thought their extinction was caused by over hunting by New Zealand’s first Māori settlers. The moa were an easy source of food, and their skin and feathers were also used for clothing. Using DNA testing of moa bones, scientists have recently worked out that there were 10 different species of moa in six genera. This is much fewer species than originally thought before we had DNA testing.
Each of the six genera of moa had different shaped beaks and gizzards (a muscular part of the stomach where food is ground, often with the aid of swallowed stones and grit), meaning they ate different plants and often lived in different habitats – for example, some were coastal, and others lived in the high country. The scientists have collected around 1,500 pieces of fossilised poo (politely known as coprolites in scientific circles).
Scientist Dr Jamie Wood from Landcare Research is going to remove and analyse DNA from all the coprolites to work out what species of bird they belong to. Many will be moa, but he also thinks that some of the poo will be from other extinct species of bird the scientists are also keen to find out about.
Dr Wood will also examine the preserved dung for seeds and leaf fragments to see what plants the birds ate. By doing this, he will be able to record diet data according to species, ecological zone, gender and even season.
The scientists say the study will dramatically improve our knowledge of ancient New Zealand and will provide a comparison of the impacts of moa and introduced mammals.
The team will also study soil from relatively unmodified forests across New Zealand, to examine how forest understorey composition has changed over the last 1,000 years – with moa, without large herbivores and with introduced herbivores.
