The first birds to become extinct, within a century or two after human arrival, were the largest – all species of moa, both species of goose, and both adzebill species. Being flightless, all would have been quite easy to hunt and catch, yielding large quantities of meat. Their slow breeding rate meant they were lost faster than they could be replaced.
Big geese and adzebills
The South Island goose was three times bigger than the introduced Canada goose, weighing 18 kilograms and standing a metre tall; the North Island goose was rather smaller. They grazed in open country and were flightless.
The stocky North and South Island adzebills were similar to the geese in weight, and 80 centimetres tall. Arising from the same stock as rails, they have no close living relatives. They were well-equipped predators, with strong feet and a bill the width of their head, tapering to a point. They might have eaten ground-nesting birds including seabirds and ducks, as well as lizards, tuatara and invertebrates.
Six ducks are now extinct, five of them within about 200 years of Polynesian settlement. They included a musk duck, a stiff-tailed duck and the stocky Finsch’s duck, which may have been flightless.
The sixth species was a merganser – a fish-eating duck with a long, thin, serrated bill, unlike typical ducks. The southern merganser, extinct on New Zealand’s main islands by the 1500s, had an isolated population on the subantarctic Auckland Islands. These islands were free of mammalian predators until pigs, cats and mice were introduced during the 19th century. The last known southern merganser was shot for Governor Lord Ranfurly’s collection in 1902.
Six flightless rails and two coots became extinct. Weighing over four kilograms, the North Island takahē or moho was the world’s largest rail – taller and heavier than the South Island takahē but less rotund. It was seen by few Europeans, and surveyor Morgan Carkeek brought one out from the Ruahine or Tararua ranges in 1894. It was identified by older Māori who still remembered them, and elders of the Muaūpoko tribe came to pay their respects.